Low sex drive 😔

So I need tips or tricks or something to help me out, I'm 20, I've been with my SO for almost 4 years now. We have sex often but normally I never want it and just have sex just to let him get off. But I want to WANT it and it just seems like I'm never horny, we do foreplay sometimes too but most of the time it'll get me wet but not horny enough to want it. Any one else have this problem or know of any ways to make yourself horny more often so I can actually enjoy the sex mutually??