Confused

I have an issue and im open to all opinions .so I was out of town for a while and my boyfriend cheated on me . He went to a woman's house and did Netflix and chill but he says nothing happen because she was nasty and that he just went to eat wings witch I believe nothing happen but I think something was going to happen and he stopped . I also found text messages to ex on his phone as well . He now has job out here and I was going back to my sister house to visit until thanks giving . So here the issues I'm scared that what happen last time might happen again although I did forgive him it's hard to forget it and I don't know what to do. I feel like I'm being pulled both ways staying here with him or going to my sis house .