Second chances (numerous times over)

The last thing I want to be is the go-to/fallback chick because I'm too easy going.  And, let me not lie, it's also nice to be taken out every once in a while and not have to worry about paying for anything!  But at what point do I finally throw my hands up and say "enough"?  It just seems to be an endless cycle of  me usually being single and him dating crazy chicks, then realizing that it's nothing but headache and drama and it coming back full circle to me again where there is no drama.  So, do I just let it keep going this time and see if it's going to go somewhere this time?  Or, do I flip him off and tell him to f8ck off already?  Decisions, decisions....