Remember Our Blessed Lady has you in her prayers!
As with anything, the first step to complete healing for the one who was wronged is true forgiveness for the one who wronged them. It’s hard, but more than necessary.
While I have never had to deal with an affair, I did experience abuse when I was younger. If it were not for our Lord’s grace I would have never been able to forgive, and without that forgiveness, I would have never been able to heal.