Then, she shattered everything. I've been having an affair. I couldn't breath. I hoped I was wrong. The writer of the preceding example omits nine minutes and 45 seconds of dialogue.
Readers miss nothing.
While condensed, the words quoted reveal the essential information. Not every statement requires a reply. Notice the word choice. The affair is ongoing. At this point it is not important when, how, or why the relationship began, so the writer omits those details.