Should I be mad??

First off I'm not against my husband masturbating but come to find out through out my pregnancy he's been doing it behind my back why hide it first of all? But what makes me really mad and hurt is that I'm always asking for sex and I always get an excuse I'm tired we will when I get home and nothing at all I'm sexually frustrated and idk what to do I don't believe in cheating I told him many times how I feel and want to have sex with my husband and he always says ok we will and nothing it's to a point where I think my desire is dying for him I'm trying not to give up but it's hard