I've been going through this with a limerant spouse. Even though she said that she wanted to stay and work on the marriage, she'd be resentful of me and view me as the obstacle between her and her affair partner. In a few days, she'd treat me awfully - not actively, but passively.

Basically, I was the thing keeping her from getting her "fix" - even though she said she didn't want to continue it.

These people are not rational. They can be the most religious church-going moral people in the world, but under limerance, they'll lie, cheat, and steal to no end. They'll blame you constantly. They don't take responsibility. It creates a narcissistic person.

This went round and round, she'd get caught, repent, be wonderful for a few days and then return to old habits almost immediately.

I could tell when she'd seen her AP, because she was immediately bright and full of life. She could see no wrong in her "soul mate" - even though she was the 3rd married woman from work he'd been involved with.

I don't think limerence can run it's course in this type of situation. The affair part of it may make it stronger as your spouse can't obtain that partner. Rick has other good info on this type of affair and you'll often get a pendulum of back and forth between relationships.

The wayward spouse either needs to go all in on that relationship with the affair partner or go all in on getting out of limerance (which will feel like death and require professional help). Not making a choice IS a choice. No choice is really really bad for you.

My wife eventually gave up all of her financial security and half of the access to her child to pursue that relationship. I filed for divorce when I began to look at her actions, not her words. You cannot fix a marriage on your own.

The sooner you give her a real ultimatum that you're willing to follow through with, the better your chances are that she'll chose you. The longer you wait, the more you lose. That ultimatum should include boundaries that involve actions your spouse can either agree to or not and specific consequences for violating those boundaries. Stick to them. Do not waiver.