I never thought I would get anything from a support group, but guess what they do....SUPPORT each other because they are going through the same thing. I found myself leaving after dinner and not coming home until I was ready to go right to bed....never even saw W most times....it was like we were living apart.Most groups meet weekly, and I also found this a great way to meet new people as the group changes a bit each time. I find myself talking to new people about new things.
What kind of support group is it? I may be interested in something like this. I have found myself talking to perfect strangers about my sitch. Maybe not in detailed terms. Like my walking group. I meet new people every week and if they ask if I'm married, I tell them a little about what's going on. Feels good to verbalize it when you know the person won't tell anyone you know or don't have a personal feeling about it one way or the other.
I agree that the person that's wayward should be the person to move out. They want that life, they have to find a way to pay for it and make it work for them. Not your problem. I would stick to your guns!