Yep, no need to ask her where she was going and who with. It is pretty self evident, so no need to go there. I know you are hurting like a SOB and that you'd do just about anything to undermine her trip and her "relationship" because in your view that might send her back to you. It will not.

No need whatsoever to ask her anything. Always take your kids if you can. I stress, if you can. If you made plans, tell her you have plans, just don't be a Richard about it. I know what you are thinking. If you dump the kids on her, than she cannot go and you will mess with her plans. While that might be true, it will not interfere with her affair. This is why it is important to GAL. Then you really have plans and are busy and you do not bend backwards to accommodate her.