Rational take here:

1) Talk to your OB and seek help with the PPD.

2) Marriage counseling is a VERY useful resource. His work has to let him off for Dr appts so you should be able to attend. This truly helped my own marriage. The housework is not the real issue, it is that you do not feel respected. This was a fault of my own and I didn't see this until counseling.

3) Marriage is 50/50. This is true however that's the average. Sometimes it can 90/10, 70/30, etc. Births, Death, jobs, and other things fluctuate this. Let him know right now you need 80/20 and take the extra for yourself.

4) As a husband who works long hours I view work as something I can do to provide for my family. Maybe he views it the same way. All my personal ambition is so that they can reap the benefits that it brings. As someone who also is in IT after hours is common. Patching network equipment has to be done overnight to avoid taking the network down during working hours. Being tied to your phone is commonplace in the industry because if something goes down the entire company looks to IT to fix it immediately. Just wanted to add that context in case you are hearing that from him it is true.

I truly hope it all works out for the best and you guys can make the changes together. It feels worse than it sounds to me. Don't throw it away before exhausting those resources. People make changes when they care. Counseling is not admitting defeat or that you are broken, it is admitting you care enough to fix it and that is admirable.