I think he is treating you like a whore, or a mistress. I also think you are young, and naive. You didn't say anything that indicates he likes you.
No, you are treating yourself bad. You are the one who is calling him to have sex with you. You said he is staying with another woman, but this does not explain much. Maybe he is staying with a female relative, friend, room mate, girlfriend, or wife.
He does not have to buy you anything. Because you clearly said all you do with him is have sex with him. If he liked you, then I think he would have already said something to you.
I think you are confused. You are not agreeing to have sex with him. You want to have sex with him, and he is agreeing to have sex with you.
If he does have a girlfriend, or wife, and he is having sex with you, then he is a cheater, and maybe a sinner as well. If he already does have a partner, then he is not a loyal man.
I don't know if you considered the possibility of him already having a sexual transmitted disease. I think maybe you should go see a couple of different Doctors. A family Doctor, and either a psychologist, or psychiatrist.