I think the best things for us were:
Not raising issues when angry. It's much easier to talk things through out of the heat of the moment.
Don't compare tiredness. Fucking difficult if you are doing night feeds, DH sleeps through and then whinges how tired he is in the morning!
Remember in your worst moments, you made that baby together, you are both to blame
but that you made that baby together, and it is the best thing in the world.
Remember too - whatever is going on, all of this will pass. We just went through the 12 month sleep regression. Utter hell, but google told us it would last for 6 weeks. So we went with it, didn't bother with the routine or stressing out, just lots of cuddles and coping, and lo and behold, 6 weeks later, things are calm again.
As for baby time, obviously you haven't said what your issues are, but again here is what helped us.
Allocation of jobs (shared cooking, I did all shopping, tidying and laundry, he did the bins and cats etc)
Online shopping and meal planning. Really takes the pressure off.
Depending on his job, shared parenting once he has finished work.
At least one night a week each off from parenting, to go out, sleep, bath, veg on the sofa, whatever.
And one weekend lie in each.
This became much easier once DS was 6months, on solids and in his own room.
Hth x