Right OP, tough love time - one of my male friends has broken a few hearts in his time while in FWB relationships.
He was clear throughout that he didn't want to commit.
He was clear throughout that he didn't want to be exclusive.
He was clear throughout that he was positive this wouldn't change - he gave no false hope at all.
But he's lovely and kind and to be honest amazing in bed!
The girls who had their hearts broken all lied to him at the start "I'm not like other girls I'm cool with casual" then got increasingly passive aggressive when he gave in their eyes the "wrong" answer to questions like yours, but would backtrack as if it was totally fine.
You know why he didn't step back and realise the women in question had caught the feelings? It's harsh but it's because he wasnt playing games. He wasn't analysing every message they sent. He took what they said at face value because he'd been honest throughout and so expected them to be as well. He's not a mind reader.
If they had said it wasn't working for them anymore or they wanted different he would have been honest (again) and agreed that's best as they want different things and best wishes etc
He won't care if you have a great night out on Facebook and you're tagged in the pictures! He isn't your boyfriend and he has done nothing wrong. YOU told him to enjoy his night out. Tbh you are the one playing games (wrong answers / how to make him jealous / thinking he will change etc) and he is being honest.
Please OP just let this one go, you aren't on the same page and I'm sure you deserve someone who wants to snap you up just as much as you want to snap them up.