That last point illustrates how these things are not a case of right or wrong- it's a case of both partners being honest and open and fair. For the partner who suddenly starts working to feel that more of the spare cash belongs to them as some kind of reward for doing what the other partner is already doing, is illogical and stupid.
There have been a lot of this type of thread lately and the bottom line is: TALK to your partner and be HONEST. Then keep talking until you have negotiated a situation that works for your family.
If you are in a relationship where you both want a balance of work and home, then there may be compromises on things like promotions. Eg because DH and I have always both worked, we've had to consider one another's careers and can't just each chase promotions which might mean moving too far away. We've also both had to share cooking, cleaning, nursery drops and on the occasions the children were ill we would alternate days off to care for them. (apart from when i worked part time for a few years and obviously did more around the house then.)
I'm not suggesting everyone else should do this just because it works for us. It suits some couples to have quite polarised roles with one doing all the earning and the other being a SAHP.
The key is to ensure both partners are happy with the deal, and then to not moan about your situation.
On the face of it, it seemed at first that the OP here was being unreasonable because it sounded like her DH was trying to tell her that he wasnt happy with having the greater earning responsibility and that he wanted to renegotiate. From later posts it seems she's saying he wants more money for a Merc and designer clothes and wouldn't step up and do more childcare anyway 
Seems to me there are bigger problems here than just the hours worked!! And why a couple have five children without talking these things through... Weird.
It's obviously the season on MN for lots of posts on this subject. I don't think the answers are that difficult to find. Talk. Negotiate. And for goodness sake when you make the most life changing decision you'll ever make- ie to have kids- do it with someone who shares your fundamental views about family.