Dogs can open up a person with autism but in general they impact people with sensory issues. And like with children, just because you had one doesn't mean you're willing and able to handle another. Dogs and children both create chaos and messes. A yappy dog is a torture from hell. Hair can be felt on surfaces, especially bed, the smell of their foods.
Accidents when new to household, destruction of cherished item (I literally came minutes away from grabbing and drowning the weasely runt of our service dog's surprise litter, when at 5 months squeezed into vent to go to forbidden room where she tore open boxes and chewed photos and a cherished at by my daughter.) They can be rude.
I OCD vacuum 3x a day, vacuum my all my clothes in closet. Have zap collars, baby wipes at door.

My X and I are both on spectrum, but he had habit of bringing things home then dumping them on me for the next shiny. Often things that were alive

You don't mention if spaniel was unilaterally or joint previously, or a gift. Obviously with length of marriage not grandfathered in. Situation.. ie., my x let me keep a pommie gifted after our first son died though he hated toy dogs. I was home alone all day and he was working/commuting 5/12 so wasn't in proximity. He got rid of him 18 months later while I was convalescing at his mother's pregnant with our daughter. He would feed and play but who didn't know he hated him except me?

The gift thing.... I love gifting thoughtfully selected things. My x and his father hated it. My mother and her father hated it. And one of my sons. 4 didn't like birthday blowouts,

PS My son absolutely had no interest or liking for dogs for 3 years after his second service dog died of Valley Fever at age 4. Even hayed them until he saw the current amiable corgi mix