NC for this one. But simply as the title states.
The wife isn't a close friend anymore. We used to work together and were pretty close back then, but she's a fair bit younger than me, had kids, quit the company we worked for and started to socialise with other young new mums etc, which is of course as you'd expect. No problem.
I still keep in light contact on FB with her and her husband, liking and commenting on posts, wishing each other happy birthday, occasional message etc. But not seen them propely for a couple of years as they moved.
She and husband been together at least 15 years both still show as "married" on FB, but not linked to each other's accounts (no idea if it's always been like this).
A few possible answers have popped into my head:
A. It's none of my business, keep my nose out.
B. If he's cheating, she should know.
C. Maybe they've quietly separated, hence back to answer A.
D. Could be a joke / fake Tinder account that the husband hasn't set up.
Anyway, just a WWYD?