My boyfriend constantly accuses me

My boyfriend of 3 years and 7 months constantly accuses me of cheating on him with his friends and people I have never met. I use to live with him and when I did I never spoke to his friends, I stayed in his room all the time because all he wanted to do was be with his mates now that I moved back home about 6 months ago he’s constantly come up with these wild theory’s that I’m seeing people behind his back. I do not leave my room , I do not go out, I do not hang out with my friends as they live away from me, and no matter how much I tell him the truth he still will not believe me and I honestly do not know what to do... 🙁