I believe I read somewhere in Shirley Glass' Not Just Friends book that affair partners who marry each other and have long lasting marriages are only in the 3% range of success. It is a minuscule success rate, if at all.
No wonder it is best to ride out your WAS' affair...and let it die a natural death.
There are two very different schools of thought on this. Those who believe that affairs are highly addictive (and I am in this camp) correctly point out "How many addictions are you aware of that, if you just leave them alone, they will go away on their own?" Don't in fact most ESCALATE?
I'm not a big fan of the "Little Bo-Peep" approach, as I guess you can tell.
The problem with the "3%" figure (and that sounds a smidge low to me, but let's assume it's correct) doesn't account for OM/OW #2, OM/OW #3, etc. Long-term successful relationships coming out of illicit affair partnerships might be very LOW, but the recidivism rate for more infidelity is quite HIGH.
Put more simply, they may not stay with their OM/OW #1, but if you don't seriously address both the infidelity and the marital dysfunction that led to it, you'll be staring down the barrel of OM/OW #2 very soon. And -- just as bad -- the betrayed spouse will ALSO be destined for failure in THEIR future relationships (assuming the marriage doesn't survive the infidelity . . . many do . . . mine did) if THEY don't address their own 180s, GAL, etc.