So he desperately wanted a dog. He also desperately doesn't want to do the work that comes with having a dog. Because that can be handled by his skivvy - you.
"I promise you never have I seen him act so incompetent in my life."
Mmm. You have, you just didn't recognise it as such.
Remember you said this - "He will pop to the shops after "work" but refuses to do anything but these rounds on a game in between his work tasks. I'm then waiting to sort dinner or start stuff so I just go myself".
This is called 'strategic incompetence', sometimes 'weaponised incompetence'. Where someone does something so badly (or in this case, so tardily) that they don't get asked / aren't expected to do it again. Ever. He'd rather game than adult. And so you 'just go yourself', doing the adulting that he has abdicated himself from.
So you see, he HAS always been like this, it's just that the dog ownership has brought his behaviour into the light for you to examine afresh. And you don't like what you see ("It's so unattractive"). Neither would I.
Frankly, he doesn't deserve to have a dog, he doesn't actually care for it, does he? Yes, I know he makes all the right noises, 'researched' it (read up on his beloved computer) expressed a preference on breed - but he's doing NOTHING for the dog. He has again abdicated, and expect you to do it all. Hasn't he trained you to do it all? With his strategic incompetence?
Consider whether to rehome the dog, and get him a tamagotchi instead.
And absolutely DO NOT HAVE A BABY WITH THIS MAN. Because this should have taught you that he will continue in this behaviour and leave everything to you.
Consider whether he's worth it. Because now you've seen it, you won't be able to unsee what a sexist lazy pig of a manchild you are married to. It's enough to give any woman the ick.