I am harldy in the mood for sex anymore. Why?

I 24 female been with my boyfriend for 7 years now lliving together for almost 4 years and it came to my attention that i hardly ever get horny for the last year. He always wants sex every single day, doesn’t take him 5 seconds to get it up. I just feel like this is the only thing we do in this relationship is to have sex. We don’t go out for dinner because of financial reasons but the smallest thing matters. There no effort of doing anything at all if it isn’t sex. I talked to him about it multiple times about not making effort to do something special, haven’t seen any results so i just try not to let it bother me. If we decide to watch a movie (at home) and i lay next to him, either he want it or he fall asleep before the movie even ends. We work he works mornings and i work nights i am home 12am we are only off on Sundays all we do is stay in the house unless i am the one to plan something so from last year i stopped planning because i just feel like i am taking my self out. There is no effort to do anything else but sex for him. No interest in trying to grow closer to God as a couple. Nothing but sex it’s always about sex. These days when we have sex he always wants to do the most and i honestly don’t like it i rather have vanilla type of sex but i guess i have to compromise and please my partner by “exploring””spicing up the sex relationship””trying new things”. He always say i am boring when i tell him i don’t like doing the most. I don’t mind doing it occasionally but everytime when he wants sex i suddenly feel so tired and not in the mood at all. Now i hardly ever get horny only after my period and i don’t even masterbate. He realize that i am hardly ever in the mood and say we should talk about it. I said that only thing we do in this relationship is sex. He mentioned maybe it another guy why i am never in the mood sigh don’t know if he believe that but it’s nothing like that. I honestly don’t know why my sex drive is so low and i am not turn on or not in the mood to have sex majority of the time. I feel bad because he saying he always have to be begging for sex sometimes i would give him but he feels the energy that i am not in the mood. I honestly do know it’s like if he asked for sex today and i said no he just feels obligated to get it the next day sometimes i would think i wish i gave him yesterday so i dont have to give him today. Sigh i don’t know whats wrong.