1 She cheats
2 You expose it
3 She cheats again
4 You expose more
5 She cheats again
6 You get a separation agreement and ask her to take her affair out of the family home
7 She cheats again
8 You expose AND pack her bags
9 She cheats again
10 You get a lawyer

You see here there is no talking, there is just action based on her choices... stop the negotiation, she's just going to

Promise you she will stop, but she will go underground instead

She makes a commitment to stop
You monitor for a week
She cheats again
You ACT

There is NO TALKING here, you just DO