Agreed. She’s his girlfriend, not his ISP.
I’ve been in this situation myself, and it didn’t end well. Like it was said above, if he’s doing it to Susan, he’ll do it to you.
I know how it feels to like someone and to feel that little bit of power when he hugs and kisses you rather than his girlfriend, even if she is your good friend. It makes you feel good to have his attention, his focus.
But he knows exactly what he’s doing and my advice is to have a nice long chat with Susan. Tell her what’s going on, and go from there. Whether you admit to her your feelings for him is up to you, but at least let her know of his behaviour.
It sounds to me like this guy is way too good at flirting without being seen by his girlfriend. Like maybe he’s had a lot of practice?
I’ve been the one cheated on by such a guy. Trust me, it isn’t fun, and it was worse when I found out it was with people I considered friends. Nothing justified it, in my opinion, and four years later I’m still not speaking to those people.
Friends are more important than most young love, trust me - cuz when that awsome, nice guy dumps you, they’ll be there for you in the end.
~Tasha
Yes. He does.
I am willing to suspend judgment as to whether he is a bonafide cad or whether he is simply too young to realize that he needs to take affirmative action to release Susan before he starts looking around. (I’ve known guys who were really the epitome of the Lovin’ Spoonful’s Did you ever have to make up your mind?. They were not malicious, but they were definitely clueless and they caused just as much pain as any cad could.)
But no guy flirts with one specifc woman while dating another without “realizing” what he is doing. (Flirting with every skirt in the room is a separate issue.)
Man, that sucks. I’ll let other, wiser Dopers provide their sage advice. I just want to say, I’m sorry you’re in this situation.
I agree with most of LunaV’s post, except for this last bit.
Maybe between two guys, a conversation like this wouldn’t end in disaster, but between two 20?ish women … I don’t think so.
The OP has described Susan’s feelings for this guy as “she’s smitten” and I don’t think that Susan will take Buckler’s information well, no matter how tactfully and gently and heartfeltly (?) it is provided.
I think Buckler should stop seeing or talking to this guy privately. She should say “You are my friend’s boyfriend and this isn’t right. Your behaviour isn’t appropriate and it’s disrespectful to me and Susan, and it makes me uncomfortable.” Repeat as required.
To Susan, she should say nothing at this point at least. Maybe a comment that “Wow your b/f sure is a flirt hey?” … and then if Susan is curious, let HER ask the questions and lead the conversation. My money would be on Susan not wanting to hear anything of the sort.
And, Buckler, definitely don’t tell Susan of your feelings for her b/f. I don’t think he is the person you believe he is - I think you are seeing the person he WANTS you to see.
Take the high road - you won’t regret it. There are millions of guys out there who are better catches than this one.
Plenty of people have givern advice, but for whatever it’s worth here are my two cents:
First and foremost, if you care about keeping your friendship with Susan you probably shouldn’t date him at all. I suppose that somehow the circumstances might work so that you won’t lose her friendship (or at least severely damage it), but that really doesn’t seem likely to me. This is pretty much independent of whether you and her boyfriend are acting with good motives. Even if you decide that you can sacrifice your friendship for him I would say it’s a good bet that he will probably end up doing the same thing to you that he did to your friend. I think this is less certain than that you will damage the friendship, but I think that it is still pretty likely.
I think at the end of the day, it’s not about whether he’s malicious or not, and it’s not about how you feel about him, and it’s not even about Susan. It’s about you.
He’s your best friend’s boyfriend. Do you really want to be *that * girl?
I’m about the same age as this guy, and I agree that he knows what he is doing and what it is doing to you. We can be clueless, but not that clueless.
My advice would be not to have any contact with him other than that which is through his girlfriend. And do not clue in your friend about what was happening before–it just wouldn’t end well. She will realize what this guy is like soon enough, and she shouldn’t have to realize it and not have you to support her.
That told you all you needed to know. Guys don’t drop in casually to chat for four hours. We just act like it’s casual. This is a fact.
I also disagree with this last bit. Such a conversation cannot go well, it will never go well, whether it be with men or women. Say it to a guy, and you’re calling his girl a slut and she’ll just deny it anyway. Say it to a girl, and you’re just jealously ruining her ‘perfect’ romance with Mr. Wonderful. It’s way easier to just tell him to shut up and eat the cake he’s already got.
Your friend won’t thank you, she really won’t. Good luck.
Ok, I thank everybody for the replies and advice, But I think, due to the melodramatic mood I appear to have been in last night 
, I didn’t make a few points clear enough. So, since I’m feeling a bit less like a teenager today, I’ll try again.
Everything but the kissing on the cheek has happened in Susan’s view. She seems unperturbed. Also, he was on those occasions, slightly drunk. I think perhaps when he is sober he can be concerned enough about Susan not to take it that far, but when drunk, he forgot.
As for the car accident related phone call - I didn’t tell that story very well. When he rang, and found out she was there, he still intended to come over and did. When he said ‘never mind’ it was more like he was in the middle of a sentence and decided not to finish it. Not that he decided not to turn up because she was there.
I wasn’t looking for reasons not to pursue him or advice on how to ‘get’ him. I don’t mean to sound rude or ungrateful for all the collective wisdom that has been offered up, but I already know I should not pursue him, I can already see that it would be a bad idea to date him with expectations that he wouldn’t simply repeat this pattern with someone else. I already know that I ought not to be the person who does that to Susan. Thank you for fortifying my feelings in that regard.
And just to clarify - I really haven’t put this guy on any kind of pedestal. He is generally acknowledged by most people who know him to have the traits described at the beginning of my post. You are all correct- of course he has bad qualities as well, nobody - including me - thinks he’s perfect.
I don’t imagine myself to be in love with him, I’m not that naive and I have ABSOLUTELY no plans to pursue anything with him even if he presents me with an oppurtunity.I never did. I have a crush on him and I’m trying to deal with that. I do not wish to act on it, to entice him away from his girlfriend or to break them up. I totally get that there will be many a crush in my future and I won’t be missing out on some amazing experience by not being with this particular. I’m simply trying to get through it, since I recognise I’m not in a position to pursue anything. If it came to my having to outright reject an advance from him in order to save Susan’s feelings, I’m confident that that is what I would do.
I like Susan very much and will choose her friendship over a crush any day. Because she is a close friend who I see 3-4 times a week, I end up in his company as well 90% of the time. I try, obviously not to accept every invitation - they ought to spend time ‘alone-together’ and I make sure I don’t ‘third-wheel’ - I only join them now when Susan insists I come. Plus we often get together as a group of 7-8 people, but I can’t seem to lose them even by trying to concentrate solely on my other friends. Because we are so close, Susan has no issue at all hanging around me with her regular frequency - with him attached. She has repeatedly commented on how much she likes this. To her, it’s the best of both worlds - she’s hanging out with her boyfriend and her best friend all at once and everybody seems to get along swimmingly. She doesn’t seem to notice or react to anything he says/does with me that I consider flirting. She is (and I quote) ‘So glad that you two get along so well!’.
I do think he cares for her as well, despite how he must have come off in my first post. I also believe he has no intention of breaking off with her anytime soon, which just makes his flirting more annoying, because I get the feeling he’s just indulging himself.
Right now, I just want him to stop flirting with me. Because it makes it that much harder to forget about him when I get what feels like signals. And because it forces me to be constantly on my guard when I’m just trying to hang out with my friends. I always have to check myself and make sure I’m not feeding his behaviour, not initiating the flirting, not giving him signals. Not being able to just chill out with people I like annoys me more than anything else I think, I feel like my social life has been hijacked by this.
I want to be able to have a good, relaxed time with my friends, he & Susan included. My feelings, which I have always found easy to hide when I’ve wanted to, are harder to ignore with what feels like a a barrage of hints. Knowing the way my crushes usually go, this will last a while, but eventually I’ll snap out of it.When I have feelings for someone they do quite deeply - as I have said - but I know how to deal with that, I can live with having unrequited feelings for someone for quite some time, I accept it.
What I have done before is simply this: wait it out, accept that I cannot be with the person, enjoy appreciating them quietly and from a distance. Eventually, I can put it behind me. What makes this situation different from my past experiences is that the other guys have not seemed particularly interested whereas this guy does. I was whinging, basically, that his behaviour is complicating my cunning plan of leaving my feelings be.
I can see why some people think I ought to tell Susan, but respectfully disagree. She would not take it too well, no matter how much sugar I sprinkle on in the delivery.
My main worry about confronting him is his possibly mentioning it to Susan. It would come off to her as though I was jealously assuming her boyfriend must be interested in me.
I think what I might do is confront him without saying that I feel he’s flirting with me, but that others do. I, of course, have no idea if others have noticed his behavior or not. But I may just say, next time he wants a hug or whatever - ‘Look, I know you’re just having fun, but people have been talking about us and there seems to be an opinion forming that you’re flirting a lot wih me for somebody who has a girlfriend. I don’t want that sort of thing to get back to her and cause problems with you two. So maybe we should just tone it down, I think this is the sort of thing they’re seeing as flirting.’ Maybe chuck in a joke, as I am known to be of the two in-house-comedians of the group, always trying to make people laugh.
On top of which, I am going to have to just be a bit of loner for a while and not associate with my friends, just to get some distance.
So, what would the flaws in that plan be?
equally so 
Ok, I laughed, I feel better, Thank you
Yes he was, but only for around two months. I started to develop feelings for him after about a month, but decided not to pursue it at that stage because I could tell Susan was clearly very interested in him, I think more so than I was/am. I do think the idea of a relationship with him was more important to her than it was to me, so I dismissed my little crush and encouraged them.
Thanks also, to the men who have come in to let me know he DOES know what he’s doing. I think I probably needed to hear that. Thanks.
Sounds excellent. And I agree that clear, but light and non-accusatory is the way to go.
He might ask though, who exactly are the " people talking". In other words who’s gossipping what behind his back. Be prepared to have a light answer for that. Perhaps you could say: " Oh, Danielle made a joke about it and Hank said…" with Danielle and Hank NOT being part of his and Susan’s intimate circle, but just people on the fringe and more your friends then his or Susan’s. Otherwise he might want to get to the bottom of the gossipping. I know I would.
Yeah, and keep us informed!
Smart.
Buckler of Swashing, I wish I could tell you that guys become easier to understand on the other end of your twenties, but they don’t. One of the guys I work with that I’ve known about a month clearly likes me. He has a girlfriend (mentioned for the first time last week), but I’m almost positive I’m not reading him wrong. sigh. I don’t think they ever become less confusing.
Why can’t girls like you ever get crushes on me?
This was good up until “we should just tone it down” - that sets up a dynamic with you and him together, and Susan on the outside. I would simply say, “You should tone it down.”
It might come to a place where you have to excuse yourself from this group for a while. When I was a single, younger student, I became fast friends with a married guy. He and I got along like we had been best friends for decades, and I was certainly interested in him as more than a friend. He was happily married, though, and I ended my friendship with him before anything got out of hand. Sometimes you have to make hard decisions to do the right thing. I missed him a lot, but if his marriage ended, it wasn’t because of me.
And I still don’t think your best friend’s boyfriend is all that great a catch, if he’s creating this situation with you. People know when they’re flirting, and when they’re acting inappropriately. I think he needs to watch his boundaries, and maybe you need to remind him of them, too.
Here’s a bit of advice that I found to be life altering:
**You cannot change anyone’s behavior but your own. **
Quit wishing that he’d stop flirting with you. If you really want him to stop flirting, simply quit responding when he initiates it. Ignore the innuendos, the lingering glances, the “inadvertent” touches. Absent a willing partner, it’s impossible to flirt. So quit waiting for HIM to change his behavior. It’s an excuse, and I think you know it.
If you had someone in your life, this guy would quickly fade into the background. But right now he’s the only person making you feel special, and that’s pretty intoxicating. Unfortunately, you’re getting your fix at your friend’s expense, and that is making you feel like crap about yourself.
I dated a married man when I was in a freshman in college. He was charming and very attentive, but at the end of the day, “charming” just wasn’t enough, not by a long shot. Because when you feel like shit about yourself, no amount of attention will override that self-loathing.
In short: YOU need to change your behavior.