I’ve had dogs for 20 years. It’s a massive commitment. These would be the main points to consider.
you can’t spontaneously go away unless you can bring the dog.
you’re walking in all weather, 365 days a year. This is non negotiable - dogs must have adequate exercise
it will require more effort to keep your home clean. Mud, hair, accidents in the house, managing illness
puppies are not for the faint of heart. They’re a lot of work and demand a lot of attention. Many novice dog owners find the first couple of years very hard
the cost of keeping a dog - it’s not cheap
Ask yourself how you would manage a dog with behavioural difficulties, should you end up in thst situation
how will you manage it if you both work? Dogs cannot be left all day
caring for an elderly dog can be very challenging
Honestly your heart isn’t in it and that’s absolutely fine and sensible. Your husband is being impulsive and not thinking things through.
you’re also pregnant with a toddler! I’ve been there. I had 5 dogs at one point. Im very experienced and even I found it difficult to manage. It was baby, dogs and then myself a very distant last!
having a dog is wonderful BUT it’s not for everyone. It’s a massive 15 odd year commitment