AJ, glad everything turned out ok. You didn't really give us any information as to what the black bear did, or how it responded, that will tell you a lot. I've had a black bear shadow me as well, in Alaska, but not in the lower 48. I've spent most of my adult life in Alaska so that's probably why. One of my biggest perspectives is if you are going to be around bears (of any kind) is to learn as much as you can about them. There are a lot of biologists that will educate you but (IMHO) they aren't as concerned about you as they are the bears. Herrera is one and a guy much closer to the forum. I will give you my knowledge of bears, and the first is (and what many folks want to know) does bear spray work? It seems to be more effective with juvenile bears than adults, and that's true if it's black bears, grizzly, or polar bears. (Also black bears may come back after being sprayed if they have taken a like to you (being sarcastic here) and are being predatory. Eskimo's will tell you it just doesn't work on polar bears and they (polar bears) surely are not intimidated by much at all. When a bear is shadowing you they are predatory. They may be working up the nerve to give you a go, or they may just be looking for an opportunity. Being there was two of you and a dog or two, probably that wasn't a serious danger in itself. Personally I don't believe bears know what they are going to do it until they do it.
Getting out of the area is a good decision. Don't run, and try to be as quiet about it as possible. Many people think it's important to yell and scream as soon as they see the bear, personally I think that's a bad idea. If the bear hasn't noticed me I'm going to try to step around a tree, and make sure he hasn't noticed me. Then the plan is (as you did) go the other direction and not run, or turn your back on the bear until you have created some distance. Then just get out of the area. Sometimes it's hard to know if they have given up on you or are just looking for an opportunity to size you up. This is given they are predatory, and not the average black bear that is going to mind his own business and would appreciate your doing the same which is the majority of adult black bears.
I don't have a lot of confidence in shotguns with pistol grips. Pick up some slugs and see how accurate you are. Many folks don't really use their gun enough to have a lot of experience based confidence in their gun. It's mostly they used to be ok with it, or how hard can it be. It's hard. Add an adrenalin dump and it get's harder. I tend to think long guns are preferable to handguns. Not because a handgun is not capable of solving the problem, but most people shoot a long gun better than a handgun. Depends on which you are. Since I moved to the lower 48 where there can be grizzlies, I think in terms of a 44 Special with a good load, or a 45 Colt, or the venerable 44 magnum as minimum for black bears. Heavier recoiling handguns are not necessary and have more recoil which slows down your recovery and next shot. Bears can be put down with a 9mm provided a good load (bullet) and intimate knowledge of body parts.
Bear in mind also that you may never run into another bear. But it doesn't hurt for both of you to be armed and capable. Unless guns are your wife's forte bear spray is better than nothing, just understand that it may not settle things permanently.
Until you get something bigger your GP100 with the LFNGC or WFNGC either one in the 180 grain or even 200 grain as that gun will handle it. I know a couple of people that, like any other round, short of a really good hit, it didn't settle the argument.
Excuse my random unorganized thoughts here.