Sex with SO?

So my SO is about twelve years older than me, in his 30's and I only see him on weekends. We use to have sex all the time but now we only have sex one or twice. Maybe he doesn't like me sexually anymore? We both have our own things to do but it seems like when I try to hint or throw myself at him he doesn't get it. I don't like coming out and saying it. He says he knows so much about me and knows me so well but I don't think he does entirely because i feel like he would get the hint so to speak? Is it because of his age? My ex was hateful and tried peer pressuring me into sex all the time but now that I actually want sex from the person I love I don't seem to get it. Is it something I did or haven't done? I've asked him numerous times if he wants to try anything or do anything differently when it comes to sex but he just says no and that's the end of the conversation. Also I blow him all the time and he hardly returns the favor. And I'm quiet so I don't say much but when I do he doesn't like keep going or I guess see that I'm enjoying it because he stops. I'm very clean I don't like being dirty so I don't think that's the issue. I just don't know what to do and if really like some advice. Please help!