Fiance depressed about being a father

My fiance and I have been together for over five years. We had our first child September 27, 2018. My fiance told me that he is depressed and regrets having a baby. Today, he told me that he likes being at work more than he likes being at home. I already do most of the responsibilities in caring for our son as it is...I wake up in the middle of the nights, I change most of the diapers, I take our son to all of his Pediatrican appointments, I'm the one to bathe the baby every time, I'm the one to feed him dinner and brush his teeth every night, etc. I let my fiance go out every other weekend to hang out with his friends. Now that my fiance tells me he's depressed I feel like I need to do all of the work with the baby but I'm starting to become burnt out and resentful. My fiance and I use to have a great relationship but now it seems like we're drifting apart. I need advice. What do I do?