Your husband wants a large dog, and then I guess he is planning on walking the dog twice a day or more, a medium sized yard isn’t going to cut it. You have a medium sized yard then you should have a medium sized dog and it will get most of its exercise within the yard, being that you live in the city and there is so much foot traffic around you should stay away from anything that is aggressive.
I would recommend a mutt from the humane society, pond of whatever you call it in your neck of the woods. A dog from there will be fixed (healthier and less likely to roam), have its current shots and be checked out by a vet all for a fraction of the price on the outside.

There is a link for a Tatra dog below, (it is not a city dog!)

A golden retriever or a collie

i have 2 great danes 3 chihuahua 3 cats and the all live pretty peaceful except my male chihuahua is pretty mean lol

german shepherd. buy from a breeder.

Mastiff. they weigh 130-170lbs but are the absolute nicest and gentlest breed around

Tatras are huge, about the size of a St Bernard. Might want to look into retired Greyhounds.

You could try an english mastif they are really big but are also very loving and loyal.you could also try a wiemeraner if you are willing to give it lots of exercisr and attention.

ooh a german sheperd because they r so easy 2 train they get along with anyone and anything. u can find one at a shelter

Rottweiler. They are just big muffins and only look mean. They are gentle and will protect your home if needed. Just make sure it is well trained and socialized. Good luck!!

German Shepards are really good dogs for what you are needing.