"I said its okay. I'm not okay with it but, you told me. And you told me I was right. But, thank you for being honest."
I have this quote in my story, and me being real, never forgive your partner for cheating on you. Your relationship will honestly never be the same after, trust goes out the window. I would say just leave them for doing so, but I know for some that's very hard, but it would be good for you. I'm speaking out of experience.