Men and sex

So there has been nervous occasions where I’ve told my bf I wanna have sex and it never seems to happen . Now he told me a while ago he doesn’t wanna be the only one making a “first move “ so I have been and always seem to get “denied “ so to speak . Now do men go through phases to where they don’t wanna have sex or is he getting something on the side . Also we barely have sex as it Is so you’d think his drive would be way high .....

Feedback or opinions welcome .

Thanks in advance