And if she were to agree to it, I think she would be honest in enforcing it. I think the guilt would eat her up otherwise.
I see you trust her. Based on your story, isn't some skepticism warranted? She began the EA before telling you "ILYBINILWY" and "Maybe Divorce". You say it was secret, involved flirty texts, and the most dangerous thing of all--she says he really listens to her. By now, you probably realize listening is relationship glue! If there was any doubt there was intention behind it, note she said she didn't mind if you dated.
She's maybe not the Devil in Disguise, but also maybe not the Avatar of Honesty?
I'm skeptical of allowing someone who's misled you to self-policy your boundaries for you. I leave the discussion of "Dinner" or "Not Dinner" to others. I have no personal experience with affairs.
