SO doesn't want sex with me. Long post

So me and my fiancée have a 4 month old son together. My fiancée used to want sex daily maybe a few times a day. Now it's maybe once a week. When I try talking to him about it he gets really annoyed and yells. He had told me that I don't make effort, when I always made the first move. So then I started doing random things to give him a hint. Last night he told me that I try too hard and said "if you stopped trying too hard then maybe I'll come around" and "you always bitch about it, and that's a huge turn off". I don't bring it up all the time only when he turns me down. He doesn't want porn cause it's not allowed in our relationship. I'm very much against it. I've caught him looking at videos of almost naked girls on Facebook and when I ask him not to look he tells me that I'm just jealous. I gained a lot of weight during pregnancy that I just can't lose now and I feel like that's why he doesn't want to be intimate with me anymore. He stopped being affectionate too. But he won't even sleep with me!! I wanted to see what would happen so I laid completely naked next to him. Didn't get an erection at all and only glanced at me once. I feel extremely unattractive and unwanted by him. I don't know what to do. I can't get rid of this weight and im so self conscious about it especially since the love of my life doesn't even wanna touch me anymore😔 we are saving up to see a couple therapist soon. But right now I don't know what to do. I've tried lingerie, but he only has sex with me then because he says he feels bad to turn me down after I tried to get all sexy for him. He just doesn't want me. Ladies please give me some advice this is really hurting me😢