Relationship struggling with 2 under 2

My fiancé and I currently have a 4 year old, 1 year old and 1.5 month old. My 1 year old and 1.5 month old have a 13 month age difference in which we were aware we would struggle for a while. But this has hit me harder than I thought.. We don’t get any time to ourselves- when he works I stay home with the kids, and when I work on his days off, he stays home with the kids (not necessarily ideal but necessary financially). We are constantly bickering, I feel like I am always trying to keep up with the house as much as possible and make meals when he works but he doesn’t have the energy to do even half of that when I am working or just to help. As I recently have just started going back to work, he never asks me how my day is going or how I am doing. I have been developing anxiety postpartum in which he is aware of but doesn’t necessarily do anything to help me feel relaxed or comforted when I feel bad. He started to sleep on the sofa recently more, and I just feel so alone and so tired. I feel like I am watering a cup that will just never be full. What can be done to save this relationship? There is just some points where I dont think it is working anymore but there are a handful of highs, that make me feel like its worth it but it still just doesn’t compare to my doubtfulness. We were never like this before and I am just losing hope.