I think it's ironic that you say that to consider a cheating spouse as an addict, and their infidelity as an addiction, "demonizes" them, Lotus. My hunch is that most people would have the exact OPPOSITE complaint: that it gives their bad behavior a free pass by treating it as some type of "syndrome."
Puppy
A more practical point is this :
Q : Addiction or no, is extended infidelity best handled the same way as an addiction?
A : Yes
Bottom line - who cares if its an addiction, its hurtful, dangerous, and highly destructive to households. The effects are very much the same, and treatment in the same manner has proven to have success - more so than simply playing softball and enabling an extended affair.
Note : I say extended because I certainly wouldn't put a one night stand as an addiction, its these affairs that go on for months and years that are the most harmful ones.
Who cares if its an addiction - it BEHAVES LIKE ONE and HANDLING it the same way seems to have much more impact than playing softball with the WS does.