My inmate is not writing me as much as I am him, what am I doing wrong?

I need sum help trying to understand my fiance he tells me he loves me and misses me very much. But he dont write me i maybe get 4 letters a month. I flood him w/letters,postcards, thats all we have between us right now. Hes in the shu at the moment. As of now i cant see him only cause he got transfer far away from me its been 4 long months. I would think he would write me a lil more but he dont so im mad about it n told him im not gonna write him until i get a letter from him. Its been 3 weeks since i heard frm him. I dont get it hes in the shu hes got nothing but time on his hands. I feel hes bs in me giving me bs how he misses me, love me. We been together for 2 years 9 months. I write him 2 times a day every other day since we been together clearly he knows i love him miss him, im loyal to him. I jus dont understand why he dont write me like really im thinking he just dont care like he says he does. I just dont understand him this shit is hard for me to deal with and he knows it and to me he dont care. He knows how i feel. I dont know if anyone can help me w/sum advice i b most appreciated thank u