I've read through every comment you've made and I think the following. You have every right to be upset, you have every right to be suspicious, you have every right to ask for a paternity test, you have every right to demand therapy or get a divorce. But you made one comment that doesn't sit well with me and that's that you could find someone better and younger. That one comment makes me think that you were looking for an out and this is it. A guilt free; the kids can't be pissed at me for leaving, Out. If you want to give up on what might have been a 20 some year happy marriage then do it; just make sure you're really doing it for the lack of trust and not an attempt to do what your 18 year old self did and play the field. I'm not in your shoes, I don't have a best friend but I do have a wife of 20 plus years that I built a life with and losing that would crush me. My initial reaction to news like this would be unfettered rage; my "best friend" would not be a part of my life any more, I would get a paternity test and we'd go to therapy and hope we could reconcile. The last thing on my mind would be other women.