Like another said the reality is that Western NTR is basically cuckoldry, so the wife is cheating on the MC basically whatever willingly or via blackmail, it would still be NTR if the wife was completely unwillingly forced to participate, however after the guy that forced her got removed, its not like anything prevent her and her husband from being reunited, again the problem is you confuse the wife cheating on the MC willingly or not, if she cheated willingly, well yea its over, but if she was forced under significant threat, well realistically its basically rape, do you mean to tell me if your lover was raped you'd consider them spoiled and refuse to ever be with them again? That would be a pretty grim mindset, here at least in this story the wife was forced to cheat, although the excuse might be fairly weak, that is because again its not truly about NTR.