boyfriend started arguments lately

Lately my boyfriend (17) has brought up random crap and makes it into an argument that is all my fault. He will bring up my exes, bring up random sex things and say I’m not attracted to him. He has bpd but skips out on his medication sometimes could this be why he’s doing this? I’m too afraid to ask him why he’s bringing up stuff because I don’t want him to be a dick to me or start something again. could he just be bored? we’ve been together 2-3 years