I think it's entirely reasonable to discuss your expectations of life and broad outlines of what you want, but also very sensible to retain some flexibility because life has a habit of throwing curve balls.
One of the reasons I partnered my husband was because we had a shared view about how we wanted life to be. We were both keen to retain our careers, and both be hands on parents, share the domestic chores etc
For us, this meant both working as professionals, but neither of us blasting ahead in our careers to the extent that we would be short changing the other on the domestic front.
However, I chose to take a step back and only work 3 days after having dc1. I returned to work when she was 12 weeks, so never had long out of the workplace, but I made a conscious decision that my career would be the one that would be compromised a bit- because frankly, I quite liked the idea of a couple extra days at home 
When dc1 was a year old, dh took a new job which had a much longer commute and was slightly less money. I had reservations, but he explained that he felt stake in his job and really needed the move for his job satisfaction. It put more pressure on me because til then we'd shared childcare drop offs etc and suddenly
It all fell to me. However as he was working 5 days and I only did 3, I really felt it would be unfair of me to object.
Op- if the deal with your dh is that you both want to retain your careers at a totally equal level, then he's probably being unfair (but TALK to him- there's nothing worse than grinding away in a job you've fallen out of love with) but if you are happy with letting him take the greater share of responsibility for earning then you need to let him have more control over his life