its genuinly anxiety inducing.
That is kind of the point.
However there are also things that can be called "sharing" (if one uses a VERY loose definition of that term) which are anything but anxiety inducing. To me at least.
For example, a harem incest game, where the MC's two sisters (or daughters) suddenly start kissing each other. To me that's just hot and not in any way a threat to the MC.
Another example, a game in which love interests are fully optional, but, if you choose not to pursue them, they might have sex with some other guy. To me, that's just inconsequential. There are a lot of women in this world, only a small percentage will ever have sex with me, and I am totally fine with that, because I am also only interested a small percentage of those women. The problem arises when I am, in fact, interested in a certain woman who then has sex with another guy. That could be NTR, especially if I had already expressed my interest. Still I am also realistic enough that I won't be able to get every woman that somehow interests me.
Actually there are only a few specific situations which, to me, would be really anxiety inducing and therefore really NTR.
And those situations I avoid like the plague.
And if those situations turn out to be actually unavoidable, that's when I will rage quit a game.
Fortunately this is quite a rare occurence.