I'm 63, married and yet often think about/feel what you describe. I think it is an "aging" thing. We've felt it, done it, thought it, explored it, etc. so harder to move "forward". I keep trying to imagine a gerontology/psychology type of therapy situation that could help.

Rereading some old books like The Dean's Watch by Elizabeth Goudge (and other of her books) helps me some. The laughter, warmth and promise that more is possible as I age keep me looking.