My wife went out with a friend last night. She chased after her when her friend and her friend's boyfriend had an argument, which culminated in her tearfully running off. My wife kissed me and said "I'll be right back." I immediately knew what that meant, four hours at a bar, staggering home with god knows who, after the closing bell. This morning she complains of "not knowing what happened after 11." and "why is my coat covered in dirt?".

This happens every six months or so with said friend. Each time I harbor my anger over her irresponsibility of not even checking in with me and the children during the night and the drinking until she's completely blackout fucked up. My youngest son insisted on maintaining a vigil by the door until she returned (I put him to bed at 11:30). She must have told me she loved me a million times this morning before we left for work and asked if something was wrong. I remained stoic and told her "we'll talk tonight."

I don't mind her going out with friends once in a while, but to the excess where she wonders (each time) if she'd been roofied- burns away my trust in her. I think her friend is a terrible influence, she's a turbo hamster incapable of finding any fault in herself.

How do I handle this conversation with my wife later?