How much should a story influence you?

I find every story unique (even the bad ones, cuz there are people that can like them) in their own way. But Ik that stories are good to make you think in a way and ignore the bad things (or viceversa).
For example, I read a story where there was a bit of cheating at the beginning and then it developed quiet nicely. I liked how their relation turned out and how they manage to go through things. I even like one of the characters.
But does that mean I should feel ok with it, knowing that they deliberately cheated and treated their other significant ones as they weren't important?
I personally have mixed feelings about it.