Your post reads very much as though you are thinking in a very binary way - GET DOG or DO NOT GET DOG. Actually, it's much more interesting than that. If you really love dogs (you in your heart, not just because you were brought up with them and they are familiar) you will find yourself with dogs in your life. And this can be through many, many ways.
Some examples. Walking a dog for the Cinnamon Trust (also a superb way to help an elderly or sick person). Fostering (this could work brilliantly for you). Volunteering in myriad ways for dog rescues - walking kennel dogs, helping to transport, doing a homecheck. Taking a rescue dog to training classes to help improve its chances of adoption. Organising a fun charity dog show. Dogsitting for all these other "mummies" when they are away for the weekend. If you find yourself talking to someone in the park and afterwards you can remember every detail of their dog, but were hazy about the walker's description - then you are genuinely a dog nut and you will find a way for dogs to be in your life, in all sorts of ways.
If you're not a dog nut, there's nothing wrong with that, but I'd enjoy my lovely clean home, my freedom to dash off for the weekend and all the other benefits of a dog free life with a clear conscience. In one sense, posting in this forum means you will get lots of dog owners all telling you how much their life is improved by owning dogs (mine is, hugely) but we are not you, and only you can really weigh up the relative value of all that's involved. You would probably have a more interesting response if you posted in the "I hate dogs" bit of MN, if there was one. Because of your upbringing you have a very good idea of what's involved with dogs and to be honest, wanting something just because other SAHMs have it doesn't really sound convincing.