Sounds like you both need to do a big chunk of reprioritising together, but he'll also need to recognise that if you go back to work ft then he'll need to do more around the house, too.
I think he's probably acting out as he's so stressed and perhaps it's all come out at once with the pressure of having to pay for the holiday as the catalyst - havign a share in the company is great money wise but puts you under a lot of pressure too, I suspect. A bit of calm, apologies all round and booking a time to have a proper talk is probably what's needed here.
The holiday is a bugger, but given that you've got a lot of financial controls in place and I suspect a decent chunk of money coming in, you can probably find ohter ways to start a savings cushion for him dropping down a gear and still take the hol.
One way to do this would be to say 'ok, then I'm going to talk to work about going back full time on X date, and let's say you'll carry on in this job for another 5 months or whatever after that, then you'll look to move to Y type of job when we'll have £Z savings cushion. A date in mind will make it all much easier for him to bear whilst you save some money.
Also, if he's only just got the promotion, then staying put for a year is a good idea CV wise. Not essential, but it would give out less of a 'it was too much stress so i jumped ship straight away' vibe.