Is it me?

Ill keep this short as possible. So my husband and i have been together for just over a year now. Evryrhing was great in bed until he started this job the begining of the year. Slowly we started to have less and less sex. Well valentine's day we had a serious argument. That kind of put a damoer even more i sex. Not to bad but i noticed a difference. Then maybe two months ago another incident happened. No cheating or anything like that but it was serious. Since, we literly have sex once a month. Maybe 3 at most. It went from 3-4 a week to 1-3 a month. Now, he said at one time that i nagged to much about not having sex. Personally i dont think so but i took what he said into consideration. So i stop saying anything at all. Also, since probly about the begining of march i have been the one to start any kind of sexual "play". Alot of the times i would just pleasure him with the good ol' mouth and all. Kinda of hoping maybe that would trigger him to do something back. But it didnt. I stoped saying anything about sex to him. Its now to the point that i literly cant even get him turned on unless i use my mouth(if you know what i mean) so as much as i like doing that, i stopped. Im so tired of being the one to start it. He shows no intrest in having sex with me. I get him being tired but yet he still "helps himself" and watches porn. But when i try to do something to him, he rejects me. Not exactly in a mean way, but he'll tell me no. And come up with some reason not to do it. The age difference is 6 years. Im younger. Literly a month we go without "the good stuff"!! Ive been putting myself down so much. Is it my body? Im not over weight at all but yet ive been working out even more that usual. Ive stopped showering with him si hes not so used to seeing my body. Hell he was being funny and asked if i wanted to mess with his "banana" and i said no. (Usually im pretty adimit about saying yes) wtf is wrong me?? Why is this man not attracted to me anymore? How can i change it? This girl is tired of "taking care" of her self!!!! Please any advice!!!?