While the Trope Codifier is on gender, this trope can also affect Race, Religion, Nationality, to even things such as fanbases and more.
See also Aggressive Categorism and the Sliding Scale of Gender Inequality.
The relationship seems to be built on a solid foundation of trust.
Interpersonal relationships are an essential part of our everyday life.
This is why I tell you not to have sex outside of commitment.
You want to find out if a man is serious about you? If you don’t – because you’re a liberated woman who can have sex whenever you damn well please – don’t be too surprised if a decent percentage of those men never call again.
Remember that Tropes Are Not Bad, and that many of these tropes are only noteworthy because of their prevalence across entire genres or societies; one example in a particular work doesn't automatically mean anything on its own.
It is only the fact that these tropes appear time and again that calls attention to them.