I'd have to agree with Eric, that there's a huge difference between exposing a regular affair and an MLC affair.
In my opinion, an affair is a SYMPTOM and an IMMEDIATE OBSTACLE. A critical piece of some over-arching life crisis that the wayward/walkaway/MLC spouse is going thru. It is, in my experience, the "tree come crashing thru the roof" (Penny Tupy), and it must be addressed FIRST, after only drug, alcohol or gambling addiction.
1. Address any drug, alcohol or gamlbing addiction. 2. Address the affair
(both of these are "separating the addict from the source of their addiction)
3. Begin to address the overall marital dysfunction, to hopefully heal and improve it and -- eventually -- fully reconcile, unencumbered by the influence of a third party.
I think there are two very distinct "camps" on this. You either see infidelity as an addiction, or you don't. Where you come down on this is going to lead you to two wildly disparate sets of advice. You can make distinctions between "exit affairs," and "MLC affairs," and "revenge affairs," etc., but it's still a great big tree come crashing thru your roof, and it's gotta be dealt with first, in my opinion.
