Why do I have to beg for sex??

I feel like I have to beg to have sex with my SO.. And then he gets mad bc I ask a lot. At first we had sex every day like 2 3 time when we would see eachother then it like disappeared.!! He always wants me to give him head and I don't like doing it if I dont get anything out of it bc I put my all in giving him head! I try and try to just talk about it to him and he gets mad that I bring it up and I tell him I feel like he isn't attracted to me and he just says he's not in the mood...(when is he ever in the mood) it just  frustrates me bc I try and do new things just nothing ever good enough