yes. in fact, we need several tags: male-cheater and female cheater for those who willingly betrayed their partners. and there are netorase/re terms in japanese to refeer to other conceps like ''I liked her first'', when the male ''protagonist'' has this girl she likes, but she gets taken (by force or willing) by another guy and the guy is just emotionaly but not trully cucked.
also we need a tags for willing cucking relationships.
I think the tag name should be "Cheating: male." and if this get approved "Cheating: female" should be it's counterpart, but i imagine this would take a lot of effort from the community to tag every different doujinshi and Hmanga on the site.
The description is wrong in this context, shouldn't it be "The main character of the story that is cheating on their significant other is a male." Beside that, wouldn't this tag just over complicate things when tagging doujinshi's and Hmanga's?
Yeah NTR is a very specific fetish that usually involves cheating, but they're not the same. If anything NTR is closer to cuckold but even then there are slight distinctions.