Masturbation instead of sex!?!?

Let me start off by saying that I am not ugly! I take care of myself and try to look decent for

my husband. However, I know he masturbates at least daily. He also carries his phone with him everywhere so that I can’t look at it. Lately, he isn’t even interested in sex. I’m pregnant, but he says that doesn’t affect the way he looks at me. So, what’s going on? Is it just easier to masturbate than have sex with me? Why would a person want their hand over a person? I don’t get it! Should I encourage him to “finish” without worrying about me? Should I change the way I look? I can’t even imagine how bad this situation will be once we have a newborn and I look flabby and gross. This causes me to wonder what he’s doing every time he goes into the bathroom, every time I leave home, every time he leaves home, etc. It’s exhausting!