Just dress pretty sexy and act very sexy... But keep him chasing, like try to get him super horny, so he has to initiate sex.
By that I mean, there are times when I just have to have him and I've never seen him almost desperate like that. We have sex pretty often and it is GREAT
I've been with some super horny chicks, and I know what you mean, but I am myself super sexual, so if they wanted it, I was down (and I generally initiate sex, because I know it makes girls feel more desired and cherished, but I think most guys don't think like that, call it society brainwashing or whatever, like "men just wanna use women" and this type of bs). Another thing to take in account is that women really go crazy for a good D, with all due respect, like the way men and women are "wired" is that women go crazy for a single man if he gives them all they want/need, and while men love the dedication of a woman, the grass always seem greener on the other side... For the most part, because our instincts tell us to impregnate as much hot women as we can (lol, I know this sounds kinda dark, but it's a bit true deep down, though a special girl can change a guy... I myself am not into monogamy really, so dunno, take this with a grain of salt).
Like while I really liked fucking those girls, they would tell me they have been dreaming about my dick and stuff like that, that I couldn't quite relate, but I liked the attention anyway. I guess it's kinda how it goes in relationships when the girl is (very) sexual and the guy is strong and masculine, aka gives her the good D.
Either way, I think the best for you to do is tease him as much as you can, you can spice things up if you can, like change your hair cut/color (or simply the way you do your hair, that can change a lot how a girl looks), wear different stuff, like sexy clothes or even costumes, so effectivelly you become "other woman". You also can try to discover something he REALLY enjoys in sex, like my ex used to lick my ear in a way I was crazy about, so I wanted more sex with her because I knew she would do it, specially when I ordered her to. You can also do other stuff like "tonight I'm only gonna give you oral", so he becomes thirty for your pussy, though this can backfire big time, I know most sexual girls really get off to giving oral... But yeah, on sumary, you can make him want sex more, either by creating an "artificial" scarcity, or changing things up so they seem fresh to him. But maybe he really has a lower sex drive. No idea.