You don't threaten or talk about it, you just do it.
This is why people stop their car at red lights ENT... they know there will be consequences if they don't. They don't negotiate with the light, they either stop the car or they plow through and accept the consequences.
What are YOU prepared to DO if she doen'st stop?
If she doesn't stop (etiher by breaking a promise TO STOP and you catch her, or by outright refusing and you catch her ) you bring consequences down on her
No talk, you just DO IT.
She will learn that when she
Takes an ACTION You will take an equal and consequential REACTION
There will be no talk, no begging, no complaints, you are just prepared to ACT if SHE DOES
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
Entangled, as I said above, this is YOUR CALL. YOU need to feel comfortable with this approach. Reasonable people disagree, but it's hardly a "90/10" thing -- more like "60/40". But if you DO go this route, THIS is the way you do it.