[gritten]

No it doesn't. Voluntarily choosing to marry someone, choosing to deceive them in such a cruel and selfish way, choosing to betray a solemn vow is not being "placed in a messed up, lose-lose situation". It is deliberate, conscious, malicious action over many years upon an innocent victim. The circumstances are entirely of his own creation. He is 100% culpable.

[foldr]

I think the point is not that having an affair is “ok” but that it’s within the range of things that not unusually awful people can do. So it’s “ok” as in “Ok, so you had an affair”, not “It’s ok that you had an affair”.