Not having sex... advice

My partner and i have been together for 2 years now. We’re in our early 20’s. Let me tell you at the beginning of our relationship, sex was amazing. We always had time for eachother. Then i got pregnant. As the months passed in my pregnancy we had less and less sex till we completely stopped because he was “afraid to hurt the baby”.. well totally understandable. It’s been 5 months since i had my baby and our sex life has been bad. Like i feel like he’s not interested in me anymore. We do it once a month max.. and if we do i feel like i have to “beg” for it. We have talked about it before.. but it seems like he doesnt pay too much attention to that conversation and doesnt care. He just says that “he’s always tired” and blah blah.. at this point i dont know what to do 😞. I feel like our relationship is just going downhill