My husband feels ingnored. Advice?

Every night when my husband and I go to bed he tells me that he feels unloved and ignored. We’ve only had sex a few times since our son was born. He’s four months old now. The want and desire is there but I have zero energy. I have no idea what to do. I have recently been diagnosed with postpartum depression. I was given antidepressants but have not started taking them yet. I’m first time mom so I’m really struggling. Any advice on how to talk to my husband is greatly appreciated