My parents were ten years apart, and married 62 years when dad passed. My wife is ten years younger than I am and we’ve been married 17. So I’ll say 10.

I would and I have. It started with licking my then girlfriend’s clit as she sat on his cock in a reverse cowgirl on the couch. I licked his cock really well, then cleaned them both once he came. He was about 9” long, several inches bigger than me. She and I also licked his cock together and I sucked him to completion. I did swallow. He sucked me as well, but I couldn’t cum. The feeling of his beard stubble on my thigh was too disconcerting.