Is he cheating on me?

OK, im absoutly in love with him and he says he loves me to. im not sure if i want to know if hes cheating on me but my heart literally hurts. We are planning to get married next spring. When i first started getting suspecious was 2 times he came home and i noticed he had scrachees on his back but i was sure i didnt do it, maybe i did though. He has this x and shes totally in love with him and he says he feels bad bcshe has no friends, so we hang out with her, shes an alacholic. Umm 2 months ago we had to move into his parents house and we sleep in the living room so we arnt having multiple times a day, we do it like everyother day. i was pregnant (miscarried) so i didnt want to hang out over there in all the weed and cigarette smells so he would go and he would stay for 3 hours. She had a bf at that time but he lived in md so im not sure how often he was around. Now he deletes text messages from her and delets certain ones he sends to her. He tells her things and when we go over and i find out shes knows and i ask him when he told her he says things like she just knew or she heard the dr in the background or you were there when i told her and i wasnt. i am a deep sleeper and he wakes up at 730 i wake up at 1030. so in the mornings he goes out. A few times he told me he was going to the grocery store and i would find out later he was at her house, but he always returned with the groceries. lately i have been going with him everywhere and we have had more then usual. I give him everything he needs and sometimes i have to like beg for him to have with me and i am very attractive, size 3 small b cups red hair blue eyes so its not like ugg i just dont know. i have asked him a few times and he says he hasnt cheated on me. oh and the girl is not that cute but she is his x so they have had and he is super hot nice cute six pack tan tall just to umm let you know.