We are in a similar situation but I think I'm more reasonable than your DH and it was definitely a joint decision.
I have my own business, with a business partner, and when you factor in childcare costs I'm a significant drain on family resources at the moment, I have some clients but very little income just yet, especially bearing in mind website set up costs and other initial outlay which I've (or rather we've) paid for rather than my business partner who is coming on board next month.
I am very lucky to have such a supportive DH, and also lucky in that we can just, at a squeak, afford for me to not bring in any profit for a while.
Because I am at home, although working, I do most of the cleaning and cooking as well. In return for that, if I need to do a bit of work at weekends when DH is here, that's fine.
He's also been tremendously helpful with the website, and more importantly, dealing with all the technical aspects of getting it online, for which I am eternally grateful.
Couple of other points - DH was already the sole breadwinner, for various reasons I haven't worked full time in a proper job for quite a while, so that's not such a shock to the system.
I have also been the main breadwinner in the past while he was studying (although earning so little it wasn't all that much more than the maintenance grant he was on...).
We both consider my business absolutely viable and he has absolute faith in my abilities and that it will be a success.
We make decisions like this together.
I think it's about give and take and supporting each other. I would have been very disappointed if DH hadn't supported me in this and had insisted I go back to 'proper' work or stay at home and look after DS full time. There's no way he would have done that though, if it was humanly possible to support me. The same applies the other way round. If he wanted to do something that involved a significant cut in our income, I would be happy to do that and support him so that he is happy in what he does.