Not that I need to - I’m single right now, but a thread below on worst breakups got me to thinking… I once came to the realization that I no longer wanted to be in a relationship, and in my mind, it made sense to tell her as soon as possible. I did so on the phone, and it only occurred to me later that it was the evening of February 13…
I think she probably thinks I’m a jerk.
So - how should one do it, and are there timing issues to be considered?
-FK
In person, if at all possible.
In a straightforward manner. Don’t hedge, don’t give false hope that the relationship may be rekindled later. If you’re going to end it, END IT. And please don’t use the “friends” line. Bleah. If I want to be friends with the person who’s just ripped my heart out, it won’t be for a very long time.
Honesty isn’t always the best policy. Be as honest as you can, but don’t set out to intentionally hurt the other person. “I don’t think we’re right for each other” is perfectly acceptable, whereas “I’ve been schtupping your cousin and she’s da bomb” may be too much information.
Timing can be important, but it needs to be weighed against the importance of not leading the other person on. So going through a big, expensive, romantic Valentines day with someone you know you’re going to be breaking up with vs. sparing them the time/expense/false sense of security… mmm, I’d have to lean toward the latter. And yeah, she probably does think you’re a jerk.
I’ll probably think of more later, but I think this is a good start.
-BK
If you want to minimize the injury to the other person’s ego, then get hit by a truck. No sense of rejection.
But if you are going to persist with the whole breakup thing, then:
Absolutely do not linger. Especially if the conversation is not going particularly well. You’re not going to be able to explain it to his or her satisfaction. It doesn’t take six hours to convey the “we’re not a ‘we’ anymore” concept to someone.
Absolutely not within 24 hours of having sex. That’s just icky.
With her, right?
-FK
Do not under any condition use the Scott Peterson Approach. 
I always thought leaving a message on the phone recorder was the best way to go.
“Hey, hon. I’m dumping your sorry ass!” [click]
As a general rule, I avoid exclusive relationships to that it’s easy to drift apart. When I’ve had to break up, I just went directly to his house and said, look, it’s not you* but I can’t do this anymore. Have a good life.
And I break off all contact for at least one year. After that, we’ve both more than moved on and can be friends again.
*I know. I know. Cheap cheap line.
If the other person cries/wants another try/etc., don’t give false hope. Repeat that you’re sorry but that you need to move on, the relationship is over. No sense in stringing someone along and giving false hope just because you’re feeling soft-hearted.
There must be 50 ways to leave your lover.
And no goodbye sex.
Long ago, a boyfriend had some of our mutual friends come over to spend the evening with me. He took off, but I was surrounded by people I liked.
(He took the liberty of inviting someone who had a crush on me as well, breaking up with me and setting me up with my next boyfriend in the same evening.)
But its about you, not them. “This relationship isn’t working for me.” “I’m not happy.” “I need to move on.” (not, “You are working for me, I’m not happy with you.”) Make it about them and then dumpee sees that “All they have to do is change.”
You walk up to her, and you say, “I break with you, I break with you, I break with you.” Then you throw dog poop on her shoes.
There for a minute UncleBill I thought you were getting religious and then you threw in the dog poop. 
I tried that once,
the divorce lawyer she hired insisted I replace the shoes.
So make sure she’s wearing sneakers at the time.
Just have to offer a different opinion on the “goodbye sex” thing - it has always worked for me ! Helps keep everything positive. And it’s flattering - at least you know they didn’t break up with you because they found you physically repulsive !
Out of sheer curiousity, what approach is that?
I haven’t ever been very successful breaking up with girlfriends, but I’ll offer up my 2 cents anyways (which you may be better to ignore).
Never go into great detail about what was wrong in the relationship. If they ask for a reason, supply one, but be as blunt as possible.
Always go on blaming yourself about the end of the relationship. They feel bad enough already, and don’t need to hear about how their possesivness or annoying, shrill voice drove you away.
I’d always prefer that someone be honest, direct, decisive, and that they waste no time. As soon as you know that there’s no potential for a relationship, that’s when you should tell them (provided that you can do it in a respectful way, preferably in person.) I agree fully with bobkitty’s preference for being dumped on the evening of Feb. 13, rather than being led on (read “lied to”) throughout all of Valentine’s Day.
Don’t break up with anyone over a restaurant meal, though. Those take way too long for any sort of comfort. The poor dumpee has to sit there through ordering, having the food come, and getting the check before they can scoot on out of there.
Don’t be an intentional jerk on the theory that “Well, s/he’ll break up with me instead!”
Preferrably somewhere in private, most preferrably in his/her house so s/he doesn’t have to drive home, or worse, you have to drive that person home. That’s one long awkward car ride for the family.
My preference? Be upfront, don’t dawdle or wait for the “right moment” and for the love of god, stick with your decision!!!
Thanks Peg.
My comment was going to be the same as her second.
Do not break up with someone in public. Not at a restaurant, a school, or some other place where the situation can become extremely humiliating for you both.
~J
a good way NOT to breakup with someone (a friend told me that he did this…I won’t belive that he actually did it though):
Go to the Macaroni Grill where they have paper table cloths and the give you crayons to doodle on the table with while you wait for your dinner. Take a big red crayon and write as big as you can, “You are a beautiful person and I have learned so much from you, but I just don’t love you anymore.” Watch boyfriend/girlfriend run crying from the restaurant in sadness and shame.
Next time, please don’t do it by telephone.
The worse thing, however, would be leaving her wondering.