do y'all know what can it be?

My hubby and I been married 2 years. Ever since after the honeymoon he never really cared much to have sex. I'm his first too. He just wants it like once a week or 2 weeks latter if I don't ask him. I know he's not cheating on me cuz he doesn't hide nothing from me and I have all his connections. I don't understand y he's in his early 20s. Aren't men in the early 20s want sex more? So am I in my early 20s. Maby it's just me cuz I crave for it at least 2-3 times a week. To hold my self back I play with my self from time to time. What should I do? Just let him want me whenever he wants me.