I don't think you're being unreasonable at all. You're obviously both bright and educated people who should be able to problem solve your way through this so...what's his problem? I use two strategies at work that might be helpful to you. One is "difficult interactions":
1. Choose whether or not this is a problem worth addressing. Seems pretty clear to me that it is.
2. Assess the facts - you know the facts as you see them...you agreed to a plan and timeline, you stuck to you plan to give him his time and space to finish his thesis, his thesis wasn't completed until X date, your timeline is now pushed back to Y date, and you now need him to cover for you at homo while you complete your school work, which is your job right now. See if there are any other facts that he would like to acknowledge. The goal is to agree to the facts.
3. Identify emotions. You identify yours ("I feel angry, tired, resentful, duped, taken advantage of, etc."). He identifies his (he may feel tired, afraid, depressed, resentful, inadequate, unprepared, like a failure, etc.).
4. Identify areas of agreement and a plan to solve the problem as well as a plan to remediate...you'll come back to the table and discuss how things are going every 3 days...you might need to remove some perceived obstacles for him to really take ownership, etc.
The other is DMAIC - it's a LEAN/Six Sigma normally applied to process improvement in work projects but can work at home too:
Define - define the problem, goal, resources and timeline
Measure - come up with a baseline to improve against, identify the current gap between where you are and where you need to be, and map out a current process flow. Try to no blame or over-state things here ("the current process is that I do everything and you do nothing" isn't a helpful starting point LOL)
Analyze - here you need to get to the root cause of the problem and find out how to eliminate it. Your husband's attitude and behavior seem like obvious root causes but there may be other issues there that are driving the attitude and behavior.
Improve - here is where you address the (or a) root cause and see how changing/fixing that helps the situation (or not)
Control - assuming you get improvement, here is where you put controls into place to "sustain the gain"
Not every interpersonal problem can be solved like a business problem but many can. I think in your case, you're both experiencing major life stressors with a small child, a newborn, and your very important school work. This is an emotional minefield for sure - if you can apply a more process-oriented approach like either one of the two above, you may be able to remove guilt, shame, blame and resentment from the interaction and get the results that you want and need.
Good luck to you...your expectations are 100% valid, you just really need to figure out what his problem is and solve it...together!