I use the term relationship mythology to mean any statement about a sexual interaction that suggests if we meet some condition, then a desirable result will follow. Both tradition and the counter-cultures propagate many similar superstitious ideas about relationships.
Most people know these ideas cannot guarantee results but behind this tissue of rational thought often rests a superstitious belief or wishful thinking implied in many love songs, movies, psychology and advertisements. If we assume the positive results are real, the fallacy behind the belief is Post hoc ergo propter hoc” after this, therefore because of this” It confuses sequence of events with a cause of events e.g. If you want intimacy, make a commitment.