Thanks to all who have posted responses. My wife and I have talked about this alot. She has know this person at her office for about 4 years now. He works in an unrelated department and there is almost 0% chance they would ever be working for one another. We have laid out some ground rules and my wife has started to talk to him about them so he understands our concerns and where we are coming from. She said he seems very cool with all of them. We'll see where this leads but right now things look very positive. We appreciate the warnings and feedback and have kept them in mind. If anyone else has anything to share, positive or negative, we would love to hear.
Thanks again.