This will be a long post and im sorry just need a little advice.

Ok so here the whole story. My boyfriend and I have been together since I was 15 he was 21. This december will be 7 years together. Well I need a little help. We have a great relationship in the beginning. About two years in I got pregnant and thats when everything started. He always told me he had a problem which was he "always got bored" in relationships. But the thing is he cheated on me twice while I was pregnant. And it always happened after an argument wed argue he would leave and come home hours later well he was cheating. We stayed together but it was hard to trust him again. Well everything was fine until later on down the road, he knew this girl and guy since he was a kid he grew up with them. Well she wanted to be with him and they talked and all this and that he even let her come between us a couple times and always started arguments and stuff to get us to break up. I used to tell him if he doesnt wanna be with me save the time and let's both move on well things got better and he started talking to her again and same thing happened. In all that happened about five times. Well I left and he begged me to come back saying sorry and he will stop n this n that so I came back. All was good. Then we had to move where we was living and I wasnt allowed to stay at his gmaws with him bc she hated me at the time so I went to stay with a friend (2 month) while he stayed there. We both agreed to take a little break to make our relationship stronger and handle our problems. He still came over to where I was everyday we had sex talked to each other all the time basically still together really until one day he took me to a dr appt and I found condoms in the center of the car. We never used them so of course I confronted him about it he tried ton play it off like he got them in case we did it again. I let it go and later that day I got him to tell me the truth and he had sex with my sister! She has always took my bfs away growing up but she was married and it takes two. I was done after that until a few weeks went by and I was still in love with him and really missed him we worked it out n got our own place again I told him he has to earn my trust again and I would never be able to fully tust again. All was good for a while he wouldnt talk to her unless I was around. Well one night I had a girls night n stayed at her place went home next morning n found cigarette buts in the ashtray. We didnt smoke that kind either. I confronted has acted dumbfounded eventually i got the truth. He had a girl n her daughter over they didnt do nothing . I stayed. He used to go her house and help around the house well i got his fb password n started looking. He @s telling her she was beautif7l n hadpr3tty eyes and etc. I told himstop or i leave n don't come back. He stopped. All was good. Now to recent i find he never fully stopped just hardly ever talk like that. Ive told him i don't like him talking to her. He don't on fb nomore. He has numbers in his phone under a different name. He deletes everything before he get home from work. One day he didn't i find massage on there from him asking about high school reunion she didn't text back unless he deleted. He don't know i know it's her. He says it a guy he works with. Anyways got up this morning look at his phone while he in shower bc i seen he had a message. It was her saying whatcha doin 1130 last night. I told him he just delete it. And he still text my sister about stuff i should do but he does before i can. He deletes it of course. Idk should i call quits? Ive talked to him abunch n he stops for a while then does again and delete everything. He still don't know i know at this point. I know he loves me n wants to be with me but his excuse all time is i get bored. Im alway keep things spiced up in bed i do everything for him to keep him and our daughter happy. I don't talk to anyone of do anything wrong never cheated or nothing.idk what to do anymore