Sharing your life with a pet takes commitment, devotion, time, effort, and let's face it money. If both of you are not "on board" then please don't adopt a dog. Pets are not for everyone and there is no shame in admitting it isn't for you.
As someone who volunteers for a couple of local rescue groups, I can honestly say that most pets that are given up are great pets. Many have the same circumstance, in that, the people who took them home were not ready to spend the time, money, or have the emotional connection it takes to keep them for life. The "new wears off" (so to speak)and the pet ends up in a shelter, where most are put down, or if they are lucky they get picked up by a rescue group and given a second chance to find the right people for them.
Think long and hard about this, talk it through, it is a long term commitment. If you decide it isn't for you, I believe your wife will understand.... She can always volunteer at your local shelter and help care for pets that need a forever home.