Before you can break your pattern, you need to understand why you keep choosing a certain kind of man. After all, how can you move past your bad relationship tendencies if you don't first understand why you have them? If you've dated more than one of this kind of guy, chances are your choice isn't accidental. You must be looking for certain characteristics: neediness, weakness, self-destructiveness. So the question becomes, Why would you want to be with a "lost soul"?
It's possible that you're simply a compassionate person who sees someone floundering and wants to help. In other words, you have a kind of nurse complex. You believe you'll rescue this lost soul, he'll be eternally grateful, and, inevitably, you'll fall in love. You've saved a life — now you feel responsible for it. Admirable, but hardly the basis for a stable relationship.
Similarly, you could be suffering from Henry Higgins syndrome. In "My Fair Lady," Higgins made a bet that he could turn a foul-mouthed Englishwoman into a model of elegance and eloquence. Perhaps like him, you see a diamond in the rough and believe that you're the one who can make this individual live up to his true potential. Or maybe Dr Frankenstein is your role model. You like being in control of another person, and you want to make him fit your specifications. Once you've done your thing, your invention may lose its appeal. The truth of the matter is that mature relationship are based on two equals coming together; your partner should be just as stable (or not) as you are. Committing to someone like this is a lot more satisfying.
Another possibility is that your behaviour is fueled by insecurity. You so desperately want to feel needed that you make sure the other person is fully dependent on you and that there's no way he would ever be strong enough to leave you. Instead of shoring up your own self-esteem by finding ways to become stronger, happier and more self-assured you pick someone who is safe to love because he is a mess. This will not, however, result in a long-term, sustainable relationship. Successful relationships result from two already complete and happy individuals who, together, make each other that much stronger.
There could be other explanations for your dating pattern, so if none of these rings true, seek out the real reason. Bottom line: You need to look for someone who is your peer, not your pawn. The only relationship that will really last is one based on mutual respect, not on one person's dependence on the other. Lost souls may seem romantic — fragile, sensitive and just waiting for a saviour — but you've probably learned by now that involvement with these types of people produce unbalanced relationships and inevitably don't work out. Your goal is to get to a point where you're drawn to people who can stand on their own two feet and who have friends, a good job and a happy, healthy approach to life. If you meet a man who doesn't possess these qualities, learn to run, fast, in the opposite direction.