I have the worst luck ever with men, men have said im ‘shit in bed’

Purely used me for sex and came back again after saying its ‘shit’

I dont get any luck with boyfriends i just feel shit, someone explain whats wrong with me, no ones ever been respectful of me at all. I dunno what i want whether i want a relationship or to be single but saying crappy stuff about me just puts me down :( what can i do?