Chippin that is pure class.
It is pretty disrespectful not to even discuss, to be sure. However, I do believe that all the family need to really want the dog for it to work. Though appreciate you will do most/all the work involved. They are a major tie though, so perhaps DH is thinking, doesn't want to be having to worry about dog only being left for 3 hours or whatever.
Though he could have the decency to air his view/concerns.
YANBU.
HOWEVER
I was your DH, to an extent, did not want a dog. DH banged on about desperately wanted a dog and eventually I caved and we got one. I utterly regret it, she is a lovely dog, and I treat her with the utmost respect, but she is the bane of my life.
But it is the opposite situation to yours, ie. he wanted it, I do all the work. I wish I had said "not even open to discussion" as if I had, I wouldn't have caved. Because we wouldn't even have discussed. Hindsight is a wonderful thing!
But it's not in my nature to refuse to discuss something with DH, so realistically that would never have happened, and therefore, I'd still be back where I am!
Which is still a long winded way of saying, YANBU, but putting another point of view you might (or might not) be interested in...... Maybe DH is worried he will cave in like me when truly, deep down, he knows he does not want. I wish I had stuck to my guns.