My bf and songs

So whenever I’m with my bf and we put music on he gets really into it especially when its songs about heartbreak and cheating and “hes like oh man my heart” “noo don’t play that song” and there once was this song in Spanish that says “there lives the girl that left me” and he was like closing his eyes and sighing. And I’m just sitting there next to him like what the heck? Why is he thinking about someone else before me? Like it’s pretty obvious but when I brought it up he just denied it. It makes me so uncomfortable and insecure.