what is it that you are actually attracted to? could just be a horrible coincidence that the blokes you've fancied have been dirtbags.
do you like "bad boys?" if so, then there are plenty of guys who may seem "naughty" or "rebellious" or simply something "different" who won't treat you badly. maybe you'd fancy the hippies, or the artists, poets, or rockers and skaters. there's plenty of guys who fall into these categories, yet have the sense not to manipulate people.
i suppose this is a no brainer, but there's no magic advice that we could give you that'll just make you go *poof* and like the nice guys. that's your call to make.
the sea is wide and the fish are plentiful. and if you want to keep yourself from being "used," then just stop doing whatever it is that constitutes "use" until you are sure of what you are getting yourself into.
i use angst