Since he has found someone else. I think it is time for you to let him go and the guilt and shame. When we get in relationships we all take the chance that it might not last and are responsible for how we react to a broken relationship. Doesn't sound like you have ruined his life. Sounds like he is ready to move. You need to also. Not every thing in this world is your fault. Let go and look in different directions for a new relationship and leave his to him.
Gayle