Hello!
There are a lot of cultural views that can affect relationships, some in positive ways and others in negative ways.
Traditions views: Some relations can be negatively affected by the conservative people view that every relationship has a final purpose which is the marriage, not every people agree with the idea of starting a committed relationship.
Social views: Depending on the country and of course, of the culture, the social perception of traditional relationship is seen as something from the past. A lot of people states that there is no need of being in a relationship with only one person.
It's true that no one can certainly say how a couple should deal with their relationship but's also true that cultural views can affect relationships whether people like it or not.
Have a nice day!