Possible, yes. Probable, no. It depends a lot on the individuals involved, the strength of the bond between them, and their willingness to work through the myriad issues that will pop up in trying to navigate the transition. My guess is that most attempts at transition fail because cheating is often a sign that something else is amiss with the relationship and with the individuals in it. There's already a clear willingness to duck those important issues. All of which increase the likelihood of failing to effectively transition.
Didn't answer your poll, because I find it hard to answer a nuanced question in that clear cut a manner.
Male, Straight, Poly
“Instead of getting better and better at avoiding, learn to accept the present moment as if you had invited it. And work with it instead of against it. And making it your ally rather than your enemy.”