Wow... I must say that we have quite a few noteworthy tales here. Much as I wish I could contribute something here, the truth of the matter is is that I've never really had a relationship that ended very badly, at least not on the level that some of the others here had. Though, perhaps that's partly my fault because I've never really made much of an effort to get too serious with another girl, such as to the point where I'd sleep with her or anything. I try to keep the more serious relationships I have with some of the women I know to an intimate, yet still friendship-like basis.
After seeing how so many youthful relationships can be preemptive in their beginning, I made the decision that I'd only really start thinking about having a serious relationship like that with a woman after I'd known her for at least two or three years. For me, that seems like a decent enough amount of time to really get to know a person and see if you can build a lasting friendship with them. 'Cause that's what a girlfriend and/or wife is, right? She's your best female friend in the whole world, one to whom you can entrust almost everything with about yourself.
That and I'm really, really skeptical at times about whom I can really trust. There have been, maybe, only a small handful of people that I would say I would truly trust; and out of those, maybe only one or two women.