Got an Answer?
If I am needing their help, I tell a friend. If I just want to vent/re-hash stuff from the past, I talk to a counsellor. Most people I am friends with are not able to deal with my past crap and would need to talk to after I shared with them. Friends want to help. If they can’t help, I don’t burden them.
Trust no one
I don't think that your friends husband should have said anything, I know that my husband and I wouldn't have said something in the same situation but I wonder why you said anything to your friend in the first place. Personally I think that as it was in the past and steps had been taken to move past it and you are still together then perhaps it should have stayed in the past and if you are still struggling then you should see a counsellor.
Personally I feel that if your husband has/is making good steps to change and you accept that then telling your/his friends isn't a really supportive thing to do. It would be embarresing for your husband.
In saying that though, it happened, he is seeking help, you are dealing with it and you have a right to say, "well this happened in our lives". Your husband should be accountable for the fact that he behaved a certain way and you shouldn't have to hide that, and yes it has affected you and you should have the right to talk about it when you need to.
Also I think that you need to be careful who you talk to. Yes they might be your friend but if they are in a relationship they will tell their partner and you can't control what people say. Once you tell someone, that is pretty much it.