Responses
It's not just your partner cheating on you is considered as an experience. As a child who had a father who cheated on us many times, I still have a different perspective of the situation. I went psychological route that lust and love are separate entities and cannot be always projected onto one person, despite what the norm/society expects from "exclusive" couples.
I guess people who haven't had experience with cheaters are more open to it being used in a narrative than those who have felt that betrayal firsthand. I'm not against stories involving it, but I will say that having experienced cheating before, I don't enjoy that aspect of a story unless the author has something innovative to say about the experience, or presents it in a world where relationships are managed differently... which, looking at the raws and the fact that there's a beating and they get back together, seems like she hasn't. The resolution seems unrealistically simple and cliche with violence solving everything, following in the footsteps of most cheating manga I've read. It's like it's trying to be realistic in some aspects without being realistic in others, and it makes me feel disconnected from the story.
The way cheating is explored in Scarlet Beriko's "Jealousy" is more interesting to me - the setting is extreme (yakuza world), the roles between head, wife, subordinate, and male mistress are all blurry, and most characters aren't meant to be likable in the first place, so their behaviors are compelling in a train-wreck sort of way.