"I think that there is another man."
He laughed. "There's always another man."
"Always," he asserted.
"That's a ridiculous claim. There is not always another man."
"You think that you are not competing with some other man from the first conversation? The other man is the man she's somehow constructed in her mind. At any moment, he can alienate her affections from you. He's perfect. You're not. You, however, have one advantage over him: she can introduce you to her friends. As long as you affirm her desirability and don't embarrass her in front of her friends, he's the 'other' guy rather than 'the' guy."
"So, there's always another man."
"That's what I said."