Hi Kitty,
it's interesting isn't it, that it's rarely a consideration that the spouse of the alcoholic will go through changes and life altering ups and downs once rehab. has ended. It's not as easy as quitting drinking to solve the alcohol problem.
I went to an all women's rehab for 21 days so I can't speak about relationships between the sexes, but I can tell you that there are bonds that are formed while there and we did keep in touch afterward. The communication slowed up after a few months as everyone was finding their land legs and moving on in their lives as *non drinkers* and some simply disappeared. I believe it's natural because everyone came to rehab. very raw feeling and vulnerable and the vulnerability remains for awhile so you are right, everyone *gets* each other. (Or so we think) It's a happy yet confusing time.
That said, while I can see how your husband and his fellow rehab friend felt, they did share a kiss. I'm not suggesting that there is more to the story, but his relationship on a go forward basis with her even in a group may not be the healthiest path for them to pursue, or out of respect to you. I think a boundary has been crossed on your husbands end with you as well as between the two of them.
You sound like a truly supportive, loving and understanding woman and I commend you for this. I'm watching out for you when I say this to you.
Best of everything