Sure, and what if Dear Husband is out at work or out of the house doing something else when the dog does its business in the house--does the OP have to sit there with dog poo etc. on the floor waiting for him to come back?
We have a golden retriever, family dog, Pomeranian, DDs dog, Pomapoo, DS1s dog and 2 cats, DD2s. DS2s girlfriend stays over every other week with their chihuahua and Pomeranian. I’ve made it very clear if they get the animals they look after them. The second I think they’re not the dog finds a new home. I have found one of the dogs has done poo on the floor before, texted to find out when the owner is going to be home and left the room. Not very nice but after the puppy stage it happens very rarely. I will help out if I’m asked but I won’t do it all the time.
Also if the husband refuses to walk it, or take it to the vets is the OP just supposed to sit there whilst the poor dog is being neglected?
No, but that will be part of the agreement. As soon as DH or DD starts slacking you let them know they need to start looking for a new home for the dog, hopefully that’ll make them start working harder again and if not the dog goes to a new home. You don’t let it get to point where it’s neglected.
I agree a dog is a HUGE commitment but it’s doesn't have to be a family commitment, or yours at all. It’ll be DHs. If you really truely do not think you want to or can keep the dog then you need to explain your reasons properly and make sure that your DD understands you are not the bad person in the situation and that’s it’s DH that’s made the massive fuck up. There will reasons for and against keeping the dog but at the end of the day you have to do what you think is the best thing for the dog, your home, yourself, and your family. Just don’t make it a YOU decision like your DH has, make sure you discuss it all properly and make sure everyone understands your reasons.