confused

LaTia
I don't know what to do.. I've been with my fiancé for almost 3 years an this last year has been the worst year ever all we have been doing is fighting.! I'm no longer happy with him and don't wanna be with him anymore. But I don't wanna leave cause he has kids that I adore so much an there really attached to me. How do I leave a relationship that I'm not happy in.? He treats me like crap everyday I get called names everyday all day.. he's cheated on me, always talking to different girls.