Sometimes walks down memory lane get out of hand and can threaten to cross certain boundaries.

Atleast that was my experience about 2 weeks ago...

No issue within my relationship, no unresolved feelings for my ex, (as far as I've always been concerned my BF is The One) and as far as I know ex is happily married.
Its just that a kind of familiarity is still substantial between us. And having lost contact (he's living abroad) we never got a chance to establish new appropriate boundaries post break up, even though we wanted to remain friends.

So what I did was create those boundaries by putting the breaks on the chat regarding our sexual history. Told him that if we can't talk about the stuff that may come up in chat infront of our partners, we shouldn't be talking about those things at all.

He agreed, and because we would like to remain friends our convos have gone back to light banter between friends of old.

Maybe your situation was similar...

Idk, I hope my experience may have helped shed some light for you and your hubby.