Why doesn't he want me?

Maybe he dosen't have such a high sex drive as you because he is a little bit older? or maybe that's the way he is? He probably isn't the kind of person who likes to go out much as well, you should talk to him about it. It dosen't have to be a forceful conversation such as "Why won't you have sex with me more?" but you could ask him if somethings wrong or if anything has been bothering him recently, maybe he's worried about something or has things on his mind but also feels scared to talk to you about them? I think the best thing to do would be to talk to him and find out if anything is wrong with him, hope i've helped :)