JO SAYS:

On balance I think you should leave this poor chap alone to get on with his life, which he is clearly doing. You were unfaithful to him which suggests to me that the relationship wasn’t 100% right for you anyway. He was hurt and has rebuilt his life.

Please don’t let your envy of his new partner cause you to devastate him again. If you really love him you will want him to be happy–with her. Learn from your mistakes. It’s time to move on.