My wife, who had been using a flip phone until recently, finally switched to a smartphone. My wife didn't want to change her phone too aggressively, thinking, ``I'll only be communicating with you anyway...'' But as soon as I switched to a smartphone, my wife became addicted to it. I thought it was just the beginning...but he didn't let go even for a moment, so I thought something was suspicious. I didn't want to suspect my wife, but after finding some traces of deleted messages in the exchange, I decided to ask an acquaintance who was familiar with smartphones to restore the messages. Then my wife was having an affair. Moreover, the other person was my classmate.