Dear Book, I posted you a long answer & forgot to click on reply & it was ereased.
What I tried to tell you IMHO this has nothing to do with your AH, it has all to do with your self-esteem or self-image. If you were feeling good about yourself you would be glad he had found someone else cuz you would know he had someone to lean on & he wouldn't be bothering you to take him back. You have already left him or threw him out cuz of his addiction.
I used to feel exactelty like you about my 1st husband.
Please work on your own life & get busy restoring your self esteem ( living with an addict depletes self-esteem faster than anything )..................if it was healthy you wouldn't be caring if he had someone else.
Love,
Diane