No. I would never go.
Cheating is betrayal and a breach of trust. If my wife cheated on me I would not only hate her but want to see her and interact with her as little as possible.
For me on this trip, I would constantly be reminded of the cheating. Seeing them together happy would make me miserable.
I know you have to think about your kid and taking him into account may make this decision harder but I would still strongly suggest not going.
Women deciding to avoid men and men are calling it “man-hating”.
I’m so surprised.