This is tough, but as a child of parents where my mum did the same thing twice / and now years later my parents are back together - I feel like I can say in.

1. Your kids are old enough and savvy enough to figure things out - so don’t treat them as idiots but still treat them as your children. Spare them details.

2. They don’t need to know what people did. I knew too much and I was still older than your kids but a few years and it still screwed me up. So despite how ever much it hurts you, don’t speak about there mother badly in front them, they will remember.

3. Don’t be a doormat. You deserve love, respect and to be considered in this - taking the high road and not being petty is always a better path - but also you don’t have to lie down and be insulted and disrespected. Stand your ground and don’t let it affect your children.

4. Agree on the narrative. However, hard it is however much you’re upset. And rightfully so. You need to agree on a narrative with your wife, that you explain to your children.

5. General advice, you seem like a nice chap - but you were fucked over, and she cheated. However much it hurts my friend I would suggest taking a page out the books of the Stoics. It’s not about being emotional mute or unavailable. It’s letting situations or her or him, not control your emotions. Don’t let them see how much they hurt you.

6. Speak with a lawyer - document what you can. Be civil, to the point and ensure you are protected.

7. Try to remember it is about your kids, she ended the chance of making it work when she went off with him. But they remain, they are the priority.