It all depends on what you can abide. If you cannot abide continued, unrepentant infidelity in your spouse, than this is what I would call a "Boundary of Personal Integrity," and you would lay it at the outset. If you lose your spouse over this, then well you haven't really lost anything, because it (adultery) is something you could not have abided anyway. To use the child analogy, it would be like if your child were playing with kerosene and matches in their bedroom at night -- do you start with lighter punishments, or do you come down swiftly, since their behavior is absolutely something that cannot continue?
In cases of minor marital difficulties, or even major ones with no infidelity, I don't think an after-the-LRT or event he LRT is called for. If there is infidelity, I've seen the LRT work very well and in the case of unrepentant, continued infidelity -- esp. when the betrayed spouse knows about it, and the cheating spouse KNOWS that you know -- I think a strong case for the after-the-LRT can be made.
But it all depends on what he betrayed spouse's own core, non-negotiable Boundaries of Personal Integrity are.
btw, I have no problem with the betrayed spouse articulating their "I will not share my spouse in an open marriage" stance, but then continuing in the marriage for some period of time, while they work on their own changes and so long as they enforce certain boundaries (example: "no using our family's internet connection to text OM/OW from inside our marital home," or "no squandering of family finances on your affair"). In this case, the betrayed spouse is giving their marriage every chance they can muster, working on the changes they know that THEY need to make, and they are communicating to their cheating spouse only "I don't want a divorce, but I won't wait for you forever to end your affair." (NEVER actually COMMUNICATE your own internal deadline to your wayward spouse, because if you tell them "I will give it 6 months," you've just basically given your blessing for them to cheat on you for 179 days, at which point they will come to you and promise you the moon and the stars to give them another chance).
This is what worked for me; again, others have to decide for themselves. And dbmod is also correct in that you can't really work the steps BACKWARDS: if you've immediately gone to the after-the-LRT or even the LRT, you can't then back off and take the lighter steps.
In summary, can it (after-the-LRT) end your marriage? Yup. So you should only use it if the marriage in its current form is something you cannot abide anyway, as a matter of core personal integrity.
