I guess the first thing I would ask is - Why are you going through your wife's purse? You must already have some suspicions. Next, do you have a teenager at home? Maybe a male. Your wife may have found it cleaning up his room and wants to talk to him about it. Could be she just found it in the driveway. Kids are pretty messy. If none of this applies, she may be getting something on the side but I wouldn't mention what you found in her purse. Is she going out a lot? Maybe it's someone from her work. You'll have to do some detective work I guess.