The first time my then-wayward wife stayed out with "a group of friends" (and it was with a group, but OM was part of the group) she said she "wouldn't be home late," and texted me as I remember about 10:30 that night that she'd be out a little later, and ended up coming home at 11:15 or something.
The second time, she also said she wouldn't be home late, and came home past midnight. I then told her (and this was after I had exposed her affair, so she knew I knew) that "this isn't a hotel, if you're going to be out past midnight don't bother coming home. It's disrespectful to me, and disruptive to the kids to have you coming home that late."
The third time, it was 2am and I had shut all of the house lights off -- inside and out -- and armed the home security system. She got the message, and never did it again.
