How to forgive a partner after they have cheated?

Me and my boyfriend was together for 4 years. The relationship was so beautiful in the beginning until i got pregnant. With in the 3rd year of our relationship. He ranned around on me with so many girls. Was calling the ex girlfriends up from out of state.drivin bitches around in the car. spit in my face stomped me. dragged me out the car. we use to fight and argue all the damn time. He took me and the baby out of state to meet his family.He was all in both of those ex girlfriends faces. one ex gave him her number. and he wrote her on myspace and told her how he regret being with me and wish he could stay up there to be with here. so a couple of months after that. we broke up and that was in 2009. He left me put me and the baby out of the house. me and my son was staying at my grandmother house sleeping on the floor. and he was running around with some girl in state taking care of her and her child. and didnt do nothing for the baby. so i kept the baby from him. So a year and a half goes bye. and hes back. i was happy moved on. ANd he wanted to b back in the baby life i said that was fine. i shouldnt neva kept the baby away from him even tho me and him had issues. than he tells me that he was going with one of the bitches from out of state the one that gave him the number. and said that he wanted me back. so he broke up with her and i cut my male friend off. and now we are in counseling. and i think i can neva forgive him. so he was ova my house the ***** called his phone around 4 something in the morning and he told her that he will call her back the next day becus he wasnt going to disrespect me. He neva told the girl to stop calling his phone. And since me and him back together i feel insecure stressed out and everything. and he trys to treat me good sometimes. im just not happy and im losing my mind and i think he still have feelings for the other woman. i just dont no wat to do. Some one please help me.