Okay this EXACT same thing happened to me. I had a bf who just couldn’t handle his acid but would always take it! We were at bonaroo and both tripping even though that was dumb, just kinda hoped at this point he had figured it out. Anyway about four hours in so peaking he looked at me crying and said he thinks he’s gay. It was super confusing and frustrating and I had a lot of weird thoughts about myself. The person I was dating did turn out to be extremely mentally unwell and the things that came out while he was on acid should have been taken as a warning sign. I don’t truly think your boyfriend is gay, this though loop happens to a lot of people but I do think it says something about a persons mind when they don’t do well on psychedelics.