Your post brings back an overwhelming feeling of anger that I have with regard to this very subject! My AH went to rehab back in early March. I went attended 2 family days and couple counseling while he was there for a total of 3 visits. He was d/c on a Friday. On the following Wednesday, he had to go out of town on "business". He drove to another state to meet up with some woman he met in rehab. She even met me during one of the family visits. He stayed there for 3 nights..."on her couch". I drove there and dragged him home. I don't know if anything physical happened between them - he actually spent one of those three nights in the ER for alcohol poisoning, but the intent and emotional connection was certainly there. Of all the rotten things my AH husband has done, the thought of infidelity never, never, never crossed my mind during our entire marriage - not when he was drunk or sober.
He kept saying "She understands me. You'll never know what it's like to be an alcoholic. (You think?!?) Blah, Blah, Blah."
The pig. I could kick myself for not leaving him there. I firmly believe that connections between men and women in recovery is just asking for trouble. But I'm a little jaded on the subject...Glad to hear that your AH is understanding of your feelings and has at least discussed the subject of his new friends with you beforehand.