Premise: For two people, have some relationship, there is some order of what things are more or less private to tell each other.
Premise: The more private things are the most dangerous to tell.
OK, so how do we get the knowledge to make telling very private things safe? Intimacy (getting to know each other well -- creating knowledge of each other). The more intimacy, the more we can-safely/should tell.
So, what if people tell more than appropriate, and think they haven't messed up? It means, they think various knowledge exists that does not -- they have a fantasy relationship. By the fiat of their imagination, they've decided their partner has qualities partner doesn't. This bad.
What this got to do with discontinuity? Well, if there is an order of things to tell, and we need to create knowledge to tell later ones, then it makes sense to generally go in order (backtracking fine). A discontinuous jump from people talking about rather public things, straight to very private ones, rather than a gradual increase, indicates that a fantasy relationship has been created, or the people wouldn't think this safe.