My wife's ex-stepfather always shows up here at home, when I wasn't there

I really have no idea why my wife's ex-stepfather always shows up here at home, especially when I'm not. I know that they lived together for many years in the same house, but after he divorced my mother-in-law, he kept coming here to the house to "talk" to my wife... it must be nostalgia and affection that he has for her...