Good for you for going to see a therapist. It isn't an easy step, but really the right thing to do.
I have some thoughts after reading your question, but not sure if they apply to your situation or not. My husband and I have been through some rough patches (we seem to be in the clear now) and maybe something I say can help.
Some people say that baby blues are not just hormonal, but a sudden confrontation with a woman's changed reality after giving birth, especially after the birth of a first child. We go from being an individual to being a mother. There can be a tremendous loss of self.
During pregnancy we begin to treat our bodies as if they are not our own--avoiding dangerous foods, alcohol, etc. Once the baby is born, we become focused entirely on feeding and caring for the baby. Many of us don't want to be away from the baby long enough to shower for various reasons (lack of help being number 1). Everything changes for us. Our hormones shift and often we lose sexual desire. And then there's the sleep issue. Sleep deprivation is used for torture. We go through months without a full night's sleep. Simple things become monumental, perspective goes out the window.
For our husbands everything changes too. It just takes a little longer to catch up. They don't have nine months to get used to the idea that everything is different. They can only see us changing our focus away from them as our bellies grow. Then the baby comes and we barely even notice our husbands, except when they aren't doing what we think they should be. Even if they are lovely and supportive, this is not easy for them. They give up sex but not desire.
So here's the situation: the baby is born, we have given up everything for them, and it is a joy. But we have nothing left for ourselves. And there are our husbands, wanting to go on with normal life as if nothing has changed. They whine about not having time to workout or go out with the guys, and we get very very angry. When was the last time we got to do something just for ourselves?
Their demands make us angry because they are so out of touch with our reality.
The most important thing you can do is to reclaim yourself. Take time to yourself to be alone and not listening for a baby's cry (working helps here, but you need leisure time). I think stay-at-homes have a much harder time in some ways (yes, easier in others for sure).
And have a weekly date with your man. It doesn't have to be at night. We are both off on Mondays and the baby (now 2) is in daycare. We go to yoga, go out to lunch, catch a movie, run errands or stay home and do nothing much at all. It gives both of us some time to remember our relationship and have some fun. SInce we started doing it, our relationship has really improved. Maybe you can ask a friend to share childcare (she watches yours and hers, then you watch them) or some other solution.
But remember that you aren't doing it for him or even so that your baby can have a father. You got married for a reason. You need this part of your life back too. Don't ignore this part of yourself just to punish him.
Also look at how you share household responsibilities and if necessary, change who does what according to how much either of you minds doing something.
None of this may help. But maybe it will and is worth a try. My aunt told me that she and her husband had to reinvent their marriage after the birth of each of their 2 children. But that it was worth it and better than ever afterward.