husband cheated

So my husband friended one of his ex's which I was okay with, then she messaged him and they talked and started talking every day. my husband intended for just friendship, she apparently still has feelings for him. long story short.. she asked him to come over to her house and he went just to hang out, I had a feeling something was going to happen but he went anyways, he ended up coming home telling me that she didn't want to talk to him or see him again. He wanted to be alone and not talk about it and he told me that they kissed and he sucked on her nipple but didn't have intercourse. He told me that the next day because he couldn't tell me that and see my face. He told me that he is sorry and won't ever do it again. what should I do? I forgave him, he is no longer friends on any social media