He should have said “Yes, just don’t go behind my back.” This way she can go do exactly what she has in her heart to do and they can both stop pretending this hasn’t already been happening all along.

If he says no, then she can gaslight him with “I just wanted to see how you would respond” or “Ok, since you said no, then I definitely won’t.” He will never trust her again no matter what. He should stop being a cuck and just confront his demons.

Hopefully her plane crashes. 😇