I think you misunderstood me, I don't like Netori because of the betrayal that the MC causes to another person, because I don't want to do something to someone that I don't want them to do to me.
I like Netori only when it happens when the person in the relationship is sad with him or doesn't feel valued and the MC shows her that this can't happen anymore, and then shows her that there's another way and then she breaks up with her partner and then stays with the MC.
Until this happened to me in real life, the person who was with me wasn't happy in our relationship and then she met someone else and before having anything to do with this person she came to talk to me and I gave her the greatest strength to be happy, because she wasn't being with me.