AITA for letting my wife cheat on me instead of taking care of her kid?

So I got home from work at 1015 PM last night at which time my wife (43) asked me if it would be okay for her to go meet up with a friend for a couple hours. I told her I can't tell her what to do but I felt it was a little late to go out considering we have a 6 year old son. She's gone out a couple of times in the past with this friend and usually doesn't get back home until 3 in the morning with her last time falling off the sidewalk and injuring her knee. She said that her friend wanted her to meet her new boyfriend tonight. That's when i changed my tone. I told her she sounded like a 16 year old girl and needed to get her priorities straight. I said she should be more concerned with our child than her friends new boyfriend. I asked why she couldn't have lunch or dinner with her friend to meet her boyfriend and she said it's hard for her friend because she has kids. Her friend is divorced and the father has the kids over weekends and I don't see how this inhibits her having lunch or dinner.

Im I the asshole for not wanting my wife to leave her family at night to meet up with a friend.