Hello Wantmyhusbandback: Thanks for the additional background information. (I vaguely recall what it was like to be 40.)

This is such a difficult time of year for you to be going through all of this... with the holidays coming up plus several additional important dates as well. I do think that 40 is the age we typically think of as being the start of what we generally call the "mid-life crisis" period... mostly for men I suspect. I think that's probably around the time things began to unravel for me, although I didn't come off of the rails completely until around 50ish.
I wish I could tell you everything will be okay... or at least what to expect. Unfortunately I can't do either. I think you're probably going to simply end up waiting to see what your husband decides, unless you decide to draw that line in the sand I think I referenced in a previous reply to one of your posts. I don't know if either you, or your husband are seeing counselors or therapists for individual counseling / therapy. It might be advisable... your husband to try to come to some conclusion with regard to what he wants to do... & you to decide how you want to handle all of this. Personally I think your husband will be sorry in the end if he breaks your marriage now after 21 years. But I know it happens.

My best wishes to you...