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 wouldn't let go even for a moment, so I thought something was suspicious. He didn't want to suspect his wife, but after discovering some traces of deleted messages, he 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.