It must be so difficult for you to take in this information after so long. What caused the confession?
I would also wonder if there is anything else he is not telling me. If he confessed freely, you need to know if there is anything else lurking otherwise it will eat you up.
I'm not sure about your second question. I have heard that waywards get paranoid sometimes because if they're doing it - we could be doing it. Having said that, I did go through a period of wanted to get my own back and sleeping with someone else for revenge. I realised this was destructive though and not what I really wanted. So he may fear the revenge f**k.