The Accidental Tourist Lesson Plan

What happened in Muriel's previous romantic relationship? Why does she tell Macon about that relationship?

Only a few months before she met Macon, Muriel was in a relationship with another man. He was a customer when Muriel worked at Rapid-Eze Copy Center, and he had just gotten divorced due to his wife's unfaithfulness. Their relationship progressed slowly because of the trust issues stemming from his divorce, but eventually he moved in, contributed to the bills, and spent time with Alexander. He and Muriel were discussing marriage when he suddenly met another woman and eloped with her within a week. Muriel brings this up because she senses that Macon might leave her....