Cheating

Ok so me and my boyfriend have been together for a while and one of his friends ended up telling me he was cheating on me but all of his other friends said he wasn’t and I knew he wasn’t. I trust him and he told me he wasn’t. And I got a text from my boyfriend last night saying that someone is telling him that I’m cheating on him. I would never cheat on him ever. I would never wanna put him through that. I love him so much. And ive been trying to tell him that I have been cheating but he doesn’t believe me. He’s been cheated on in the past and I understand why he’d be hurt right now. But I just don’t want to loose him. I really don’t know what to do right bow because he doesn’t believe me and I don’t want to loose him over something that isn’t even true. People keep trying to mess with our relationship and it’s really pissing me off. We just want to be happy together. Anyone have any thoughts on what to do? I have really bad anxiety and it’s just making it all worse.