When will nice guys/girls finally finish first?

--ever heard that old saying "nice guys finish last"? why is that the case?--take me for instance, i'm a wonderful person (not perfect) but striving to be the best person i can ~ i try not to hurt ppl and always force myself to do the right thing ~ i'm a great lover who will do anything to please my mate as long as it's not against my morals or against the law ~ still, i find myself unable to find a mate that has a genuine good nature and respects and appreciates my good nature--i've faliin in love many times and always end up cheated on or abused (in the mental, emotional, verbal and physical sense) ~ the nicer i am, hoping they'll appreciate it, the worse they get ~ adding insult to injury, they cheat on me or leave me for a mate who is filled w/absolute strife, jealousy, discontent and anything else negative u can think of--why do ppl choose to mistreat good ppl just to attach to bad ppl? why do good guys/girls finish last? what do us "good" guys/girls do? are u good or bad... be honest?