How do you get over this?

me and this girl started to date well i had a boyfriend at the time ya i cheated but this guy was a real jerk and i could leave him right way long other story.so me and her sneaked around it was going g8r well i finally left the jerk and stayed with her i was happy till the 26 mine and her 1 month was on the 24 we were going to hang out didn't happen till 1 or 2am she came over and stayed the night left early the next day cuz she wanted to hang out with her dying mom i understood that well she left some of her stuff her well she called me and said hey im going to come by and get the stuff and then have to leave. she came well my sister was in the car now i wouldn't of cared if hilary didn't tell me that b4 me and her got together she had strong feelings for her plus they are best friends didn't say anything just gave her stuff and walked away well 5Min's after they left my sisters ex called me and asked if me and him could talk about her i said sure he came over we talk and then he asked me if i knew where his jacket was i called my sister and asked she said "ITS AT THE HOUSE" now why would you say that if your at the house? so i thought about it well to make this short right when i called her hilary text ed me and said hey hanging out with my mom call u l8r i flipped they were together about the leave to go smoke hookah well after that night of busting her things have been weird i love her but then still pissed about that one night we broke up to fix things but things are just getting worse what do i do try to fix it or just give up?