Betty

"'What was her name? Betty?'" Mark was Betty's boyfriend whom he broke up with shortly before the events of The Room. Though Mark called her beautiful, he cites their arguments and her lack of sexual prowess as reasons for their breakup. This is only Mark's side of the story, however. Knowing Mark's character in the film, the exact reasons aren't known. Johnny was only familiar with her, taking a second to remember her name in conversation.