Wow, lots more input - thanks!
Fisharefriends, you've got a point.
He does go straight back to bed though.
DH and I have always pooled our resources since we married, he used to earn more than me, I spent some time at home when DCs were tiny, I currently earn slightly more but we've always seen wages as 'our money' and will continue to do so, therefore we will both be paying for it, I'm OK with that.
I'm very conscious of the impact a dog has on your freedom, I don't think they are. There is no plan, that I'm aware of, of what will happen to the dog when we go on holiday. 
I'm more house proud than DH, but that's saying nothing, neither of us are really. If it wasn't for our dear cleaner we'd be in squalor!
I'm out of the house from 06:30 to about 17:30, five days a week. DH, as I've said, works predominantly from home and can get a bit lonely when the DCs are at school.
I've said 'yes' BTW but DH is backtracking now saying it will be 'too stressful' for me, I think he wants me to sit up and beg for the dog now, or more likely I'm supposed to be enthusiastic but, I'm not. How do I get round this one? 