We recently adopted another male Pit and at first our female Pit wanted nothing to do with him. They didn’t fight or anything like that, but she didn’t want anything to do with him and would avoid him. After awhile she got over it and accepted him into the pack and now they’re awesome friends, etc.
The first thing I would recommend if you do get another Pit is to walk them right off the bat. That will establish a connection with them. That’s what we did with our Pits and even though she wanted nothing to do with him, she wasn’t aggressive at all.