Hi and welcome to PBF. I admire the fact you are doing some research before you get another dog.
First, there are some members here who have both breeds. Wackyjacki and Shanda come to mind. Pit bulls tend to play rough, they're medium sized dogs and they're pretty strong. It sounds like your wife may not be comfortable with this. Second, are you prepared to never leave the dogs alone together unsupervised? And there's always the possibility they may never like each other and can't get along. Many of us here manage this issue by using crate and rotate and gates in our homes. Not to be a Debbie Downer, but it's something to consider.
On the bright side, many of our dogs get along fine with other dogs, cats and assorted other critters.
Anyway, it food for thought. Please post your concerns in in the "general" or "behavior/training" section where more eyes will see the post and other opinions may help you.