So she cheated on MC by accident? What? Listen to yourself.it is cheating if it is intended as cheating but sister with vicky wasn't that since neither did that in purpose to cheat mc.
"I cheated on you but I didn't mean to so it doesn't count"
I mean come on, that's ridiculous... Again, some people clearly don't mind or even like it and that's fine but that doesn't change the fact that the netorare tag is there 100% correctly.