Not attracted sexually

I love my boyfriend and I’m attracted to him physically but not sexually... if that makes sense.. I try to be but for some reason when I’m with him sexually I just don’t enjoy it... I get turned on fine when I’m alone but for some reason when I’m with him I can’t get turned on at all but I feel like I have to keep having sex so he doesn’t get upset.. Advice?..

(Please nothing rude..)

I have been with guys I’m sexually attracted to and I used to be very attracted to him sexually, just not recently..