Ok.
I’m saying it sounds like you’re just out for pussy. Which is fine, it’s your moral prerogative, I just find it distasteful and self centered.
Yea, thats kind of the point.
Personal opinion-- it’s cheating if you are dishonest (and that includes lying by omission) to someone you’re seeing, about the “rules of the relationship.” Of course, the problem is that you alone don’t set up the rules, you and your date do. You have to make sure that both/all of you agree on what the rules are and your expectations for each other.
If you’re casually dating someone, this could be as simple as “you need to tell me if you’re sleeping with someone else, so I can make an educated decision on how risky it is for me to sleep with you.” That might be the only rule!
If you’re making more of a relationship with them, there might be more rules like “if you are going to be spending the night at someone else’s house let me know, so I can only call your cell phone in case of emergencies, not just to chat.”
Another consideration is that someone you’re seeing may want a “veto” on new people you begin dating-- I have this rule in my primary relationship (the man I love, live with, and help raise the child of). He gets to decide that I can’t date someone if he thinks the person is crazy, or a liar, or a drama victim (To be honest, I’m not always as perceptive as he is at first meetings, so I rather appreciate the help). Drama victims are bad because they’ll manufacture crises in order to steal your time. This is a pain when you have ONE girlfriend and she keeps you awake until 3AM three nights a week listening to her complain about her family and the neighbors and her job-- but when she can get that kind of attention AND interrupt the only time this week that you and girlfriend #2 could spend together, she can do twice as much damage to your life.
I can’t really tell by your original post whether you’re wishing that one or more of these relationships would get more serious, or whether you just want several women you can casually date. I could probably recommend some really good websites, but I don’t want to overwhelm you with the intricacy of seriously committed multiple-people polyamorous relationships if that’s not what you’re looking for. 
As a bit of background, I’ve been polyamorous for 10 years and I’m currently in a relationship with more than one person (and all my guys know about each other). It’s a lot more work than you would think for me to make sure everyone gets time and attention, but I think it’s very definitely worth it. I hope you find the balance that makes your love-life worth it, too!
Corrvin
I’m going to echo both Corrvin and WhyNot, and in the interest of fighting ignorance , I’ll take it one step further…
I used to think that people who dated more than one person at a time were all like msmith537, not caring about or respecting their partners, lying to them, and only in it for the sex. I used to have this image of an ideal where it could be different, but thought I was the only one.
My first time dating two women came about when I had been dating one gal for 3 months and then was approached by someone who I had persued previously and been turned down. Gal 1 and I knew it was just a ‘for now’ kind of relationship and that we were never going to fall madly in love and were honest enough with each other that I was able to tell her about Gal 2 and that I would have to break up with her to date Gal 2.
So I went to Gal 2, told her that yes, I did want to date her, and that I had broken up with Gal 1 to do so. Her response was “Oh, don’t do that! That’s why I want to date you, because I see your relationship as friends together and you’re not all clingy and possesive with each other and I’m tired of guys trying to own me.”
So I went back to Gal 1, explained the situation, and proceded to date them both for the next year (always seperately though, never all three of us together at once). I never lied to either of them. Eventually I drifted apart from first one, then the other, and over time lost track of them, but if I ever bumped into one of them, we’d still be friends.
I wound up in a couple other situations dating multiple people over the years, always being completly honest with everyone involved, but still thought they were unique situations because ‘everybody knows’ that more than two people in a relationship was just wrong and would never work out. I thought I was crazy for dreaming of other people who thought like I did.
Then someone told me about Polyamory.
I went to support meetings at PolyBoston and met dozens of others who were in my situation and heard stories about thousands of others who all thought the same thing…
That it is possible to be in a serious commited relationship with more than one person at a time. Everything from dating to ‘poly marriage’ (not legally, but in your heart and mind).
Everybody, every relationship has different rules that are decided upon by the members of the relationship. (Corrvin mentioned some of the possible rules and things you have to decide.)
So, to bring this back to the OP…
What is the edicate when dating multiple people?
There are many etiquettes used, everything from msmith537’s lying to everyone and only caring about how much sex you can get, to respecting your partners and being honest with them and trusting them.
At what point does it become cheating or a betrayal?
When you lie, or break the rules, that is the point. If you haven’t discussed any rules, then you should assume the ‘society standard’ rules apply… and you have to figure out what that means to your partner, becuase it’s her call (not yours) about if you broke the rules.
Can you hook-up with two women, have feelings for both, and still remain the nice guy you’ve always been?
Yes. Check out the Poly links above and you’ll read stories about thousands of people doing just that and some have been doing it for decades and decades all while being honest nice guys. I have done it.
And how many women can you be in love with at the same time?
That depends on how big your heart is… and your defination of love. I personally have been madly, head over heels in love with two women at the same time. I would have died for either one without a thought. I have also loved (emotional sence) many more women at once, but then I still love most of my ex’s and have loved them enough to let them go on with their lives when I knew we were drawing apart.
Only you can answer for yourself how you feel about your partners and what type of relationship you want with them. And only they can answer the same for you. the relationship you make will lie in the subset where you and her ideal overlap.
It took me a years soul searching before I ‘came out’ as polyfidelous, and I can’t ever go back. It’s too much who I am and what I want and think possible for relationships.
Hope this helps. Good luck.
And what other reason would someone be dating two girls at once?
Look…if there’s one thing I know, it’s that I’m usually right about everything. Forget the bullship hippy crap because that doesn’t work for anyone unless you are Hugh Hefner or a cult leader or something.
DIVERGENCE OF AN ENIGMA, you have three girls you like. Are you in a committed relationship with any of them? Have you been dating for any length of time? Have you expressly stated that you are not dating other people? If the answer is “no” then you are well within your rights to just go ahead and date all of them at once as time permits. Is there any reason to be “open and honest” and tell them about the other women? No. It’s none of their business. It’s not lying.
Now a couple of things are going to happen. As your relationships progress, the women are going to start demanding more and more commitment. At some point the “are you dating other people?” question will come out. At this point, assuming you want to be relatively honest, you WILL need to either pick one because most people don’t want to share a mate or hope that they are happy with you never taking the relationship to the next level.
I’d also have to mention that no matter how big your heart is, there are STILL only 168 hours in a week.
At this point in my life, I couldn’t possibly fall deeply in love with anyone else besides the four guys I’m seeing, because I simply don’t have time to see anyone else for long enough to fall for them.
Love is infinite; sleep is not.
Corrvin
Uh, have you read this thread?
Msmith I say this completely without sarcasm. I look forward to your relationship advice nuggets more than any kind of post by any other kind of poster on the board. Really someone needs to give you a column.