Case. One partner is emotionally invested in texting someone else; there’s no physical affair, but intimacy leaks outward.
Model. Part of the intimacy traffic leaves the couple’s perimeter. Formally “nothing happened”, but the resource that held the system is redirected.
What helped. They acknowledged the problem without minimizing; returned emotional openness inside the couple; agreed on boundaries for outside connections.
Lesson. An affair isn’t only about the body but about where intimacy goes.
See Perimeter defense.