He won’t let me know what happened

Back in November me and my ex fwb hooked up for the last time ever, we ran into a problem during intimacy and right after it happened we were kind to each other about it and he told me to not be so embarrassed as in his words “it’s not that deep”. He drops me off back home and I text him saying that if he needed a break from doing anything or if he wanted to stop altogether that it was fine. He again reiterated that it wasn’t that deep and when I emphasized that whatever happens we should communicate he started leaving me on read and kept leaving me on read all for him to text me 30 mins later saying “don’t text me for a while, just trust me, after u see this don’t reply, if u don’t listen to me I’ll have to block u”, I comply and don’t text him and 2 days later he blocks me.

I wait 3 more weeks and dm him via instagram, I was as gentle as I could be, I let him know to tell me if what we have is over or not, and that I didn’t wanna wait for nothing (in the case he was breaking it off for good). After a few days he blocks me there too, now I had no means to contact him. He refused to look at me, talk to me and generally acknowledge me when I’m in the room. A mutual friend of ours asked him about me and he said: “me and op don’t really talk so I figured what’s the point and I blocked her”. ????????

That was 1.5 months ago and it’s been radio silent until today, I had the opportunity to confront him so I did, again wasn’t harsh. I walk up to him and he immediately goes “can I help u?” I’m a bit taken aback but I ask anyways: why did u cut me off? What happened?

He went on to ignore me and look down at his phone and blast music in his ears for 20 minutes as I tried getting him to talk every now and then. I got up and said “don’t try coming back and apologizing” and left, idk if he even heard me.

Idk why he refuses to tell me what happened, I would’ve been completely understanding if the last hookup made him distance himself but he won’t admit to anything let alone talk to me. Why is he doing this? Does this happen often? How can I get clarity without bugging him? I don’t want him back, I’ve just been driving myself crazy over being so clueless on the whole thing.

Any advice would be great thank u.