In my H's case, there was depression through the entire MLC and for about 9-18 months after acceptance, though it was lessening after he came out of Withdrawal and was in shorter episodes once he'd had some "clarity."
The OW has to be gone by acceptance, or they're really not accepting any changes in themselves, but still clinging to a drug. HOWEVER, the feelings for her, again, take at least a year after Acceptance to subside (though they don't come up as often as they did before).
My H's relationship talks began in Withdrawal, but it was very important mainly to listen, and to keep expectations down, because the next day he might feel quite differently.
If you feel he's nearing the end of the tunnel, you must be sure you have mastered detachment (the knowledge that you'll be just fine no matter what happens with him) for the strength to get through the next part, when a tidal wave of suppressed emotions suddenly floods you. Be strong. I hope you've got lots of GAL activities lined up for the weekend!
