Shameful sex life?

My husband and I rarely have sex (my fault). I think the biggest reason that I don't want to have sex with him is because he makes me feel bad for having sex with a previous boyfriend before he and I met, he shames me for anything sexual I had done previous to meeting him. He now gets upset because I am not feeling it. I don't feel the slightest bit turned on by anything. I haven't felt the desire in months. What am I supposed to do?