When it is fmc I normally do not consider it NTR, it would be more cheating with corruption, since if they give you the options being mc it can vary whether it is NETORARE that they steal it, NETORASE that you share it, etc.I really wanted to try writing the story from a man's point of view, but I was stuck. I simply don't know what they think
If you play other netorare or netorase games, you will have an idea of why women leave or what the character (you) feels with her fetish,
in the case of netorare, there are many reasons "you are not enough, blackmail, she is a nympho, etc.", and in the case of netorase, it is that strange fetish that some men have who think that their woman is so beautiful that they have to show her to other people to satisfy themselves, what do you ask?, no idea,
I keep playing these kinds of games to find out the same thing but even after dozens of games, I still can't find answers, the easy solution would be to say "because they like it", but I think that this is not an option
PS: I will play this project in the next version to see how you develop