Backstory: 15 years ago, 21 and single, i worked in an office where everyone was friendly. We socialised together, drove each others cars and are, mostly, still friendly now.
I had a fwb thing with one of the group for about 6 months. No 'feelings', just fun. It ended when he moved away, no problem, we texted occasionally etc.
Fast forward to 2 years ago when he finally gave in to social media and added me. Saw he was married, great. Looks happy. Text him and said 'you kept that quiet, well done!' No big deal.
Today I noticed him tagged in a post. Wedding photo (which I'd seen) which his wife had captioned '15 years, still love you the same. Thank you!'
I text him to ask how long he'd been married, no response. I've asked our colleagues/friends and no one knew he was married.
My aibu is: I feel like a stupid little girl. How did I not know? I never had any feelings for him or anything so why do I feel so sick?
BTW, I've blocked him and have no intention of confronting or anything but I can't stop thinking about it!