our two vehicles. um, at her mom's house. >> reporter: but david insisted he'd decided to end the affair. he told becky it was over. >> i'm like, "look, this is getting too close. i don't want kay to find out. i'm, you know, i'm done with it. you know, i'm done with it. you know, i'm done with- done seein' each other." >> reporter: at least, that is, until his young son derek went off to college. >> i've told her multiple times that i did not, you know, want the situation to change at home. >> because of derek? >> right. >> reporter: right after david called it quits one month before the murder becky decided to confess to her husband tony sending aftershocks across the lawn to kay's house. >> she told tony everything? >> yes. >> and tony picked up the phone and called kay? >> yes. >> reporter: the secret was out. >> i know that hurt her so bad and i apologized to her so much. she said she'd forgive me and