I need boyfriend advice?

alright so my boyfriend and i have been dating for about 5 months now. In the beginning of our relationship, and incident occurred where he called me crying saying that his roommate asked him to have a couple beers with him and he did. When he got into the room his roommate's girlfriend and her friend were there. Apparently, her friend tried kissing him and he pushed her away and she bit his neck. Now this didn't seem to likely. But i didn't want to start a fight. So I let it go. Now more recently, he sleeps over every weekend. And last weekend he didn't stay on Friday. He refused to because "my friend needed me" This seemed very weird to me. Then saturday night he told me that he was sleeping over his mom's house because his grandmom was going back to virginia on monday. I was upset, but i let it go and he promised to stay on sunday. Sunday night, i ask him what time he gets done work and he says :oh my mom wants me to sleepover again idk when i'm ever gonna see my gram again you have to understand" We got in a huge fight because i said "i do understand, it just would have been nice if you told me" apparently i was out of line saying that. There's this girl That stalks him on facebook. They used to hang out and stuff. She likes all of his posts and pictures and stuff. and one time she commented on one and said "hahahahah<3" so said the exact same thing and put eww^^ . Lol but that was months ago. so a few days ago i found out she blocked me. I think it's a little weird that she randomly blocked me out of nowhere. When i said something to him, he started flipping out saying I was accusing him of stuff, when all i said was "eww that stalker ***** blocked me on fb lol" Him and his ex had a fight over her once before. Lately,we haven't been having sex. Like at all. and this friday he told me he was stopping at his mom's after work then heading over my house. He texts me while he's at his mom's " I love you baby. I miss you so much I'm so glad i'm sleeping over! :)" that seems weird to me, but i let it go. When he got to my house he told me to feel his hair, so i did. and he says "isn't it soft, i took a shower at my mom's house" That seems weird also. Later that night we started ya know, getting into it.. lmaoo and he was taking FOREVER to ***. He actually didn't ***. He got too tired and fell asleep.. That was extremely weird to me, considering we hadn't had sex in forever.... what do you think? what should i do?