Why would being angry be sooo bad? Clearly you are not an angry person, and this might be a good 180. I agree with all of the posters above.

Smiling and waving and coming in last! WTF? Seriously NLT he has crossed a real boundary here imho. My trying to be 'civilised' about OW led to my xh telling me that I had given him approval.

They are really messed up and maybe spelling out that you really are not OK with all of this, that your daughter is not OK with this might give him pause, or at least get it into his pea brain that what he is doing has consequences.

As for black and white thinking - some things are that simple and adultery is just plain wrong. To pretend otherwise is foolish