Your instincts are probably right. Wish I had trusted my instincts more and left years ago. If I had, I'd be past this and have moved on with my life. Hope it works out for you.
My ex had a guilt trip and told me about his affair. My friend had just been murdered, I was 6 months pregnant. He had just one to many shots of Jack and his guilt hit so he decided to share,like a dumb a$$ I stayed. I was scared, I was pregnant, my mind was not really in full function mode with the family crisis I was in the middle of. I think I stayed because at that time I didn't are either way. The second time I was beyond caring, I stayed because it was easier to stay than it was to leave. I had two kids then. The third time he was in Germany, it was our 11 year anniversary, he called me so drunk telling me about how free the woman were and that he was loving, "loving" them. I think he thought he was talking to his brother. He came home, I kicked him out a week later. I had had it.
If he is lying now he will lie again. If he is cheating now he will cheat again.