Scary things happen and get the cat terrified, so he lashes out.

First the pain of the charlie horse, which must have had BF and you both making unusual sounds, plus it would have changed the chemical scent of BF, then the phone alarm.

Maybe I read to quickly, but I didn't see that the cat ever attacked you at all, just BF. That is the source of the strange things which happen, and kitty gets frightened.

I too would pick the cat and ditch the BF.