I knew a wonderful woman who used to knock on hotel doors late at night, and was quite happy as a mistress. We fall in love with whom we do, there is not much more to say.
In your situation, where divorce is not a possibility, that is for the most part, for the best. Divorce is harder on children than a parent's death. Or so studies have shown.
Life offers us what it does, take love where one can find it, if finding it at home is non-existent. To have stayed steady with one, and now be done, is a tribute to yourself and her, either or both.
I am not here to judge just to listen to such tales and give what little advice that seems to be true.
#Borc