Oh Walter: did he know that the most intriguing thing about him, in the months when Patty was getting to know him, was that he was Richard Katz's friend? Did he notice how, every time Patty saw him, she contrived to find nonchalant ways to lead the conversation around the Richard? Did he have any suspicion, that first night, when she agreed to let him call her, that she was thinking of Richard? (2.2.320)
"Look," she said, "you have to swear not to tell Richard," although she realized, even as she said it, that she'd never quite understood this prohibition, "but Eliza has leukemia. It's really terrible."
To her surprise, Walter laughed. "That doesn't seem likely."
"Well, it's true," she said. "Whether or not it seems likely to you."
"OK. And is she still doing heroin?"
A fact that she'd seldom paid attention to before – that he was two years older than she was – suddenly made its presence felt. (2.2.394-397)
"Here's the choice," Richard said. "We stop now, or you leave Walter. And since the latter is not acceptable, we stop now."
"Or, third possibility, we could not stop and I could just not tell him."
"I don't want to live that way. Do you?"
"It's true that two of the three people he loves most in the world are you and me." (2.3.431)