Larry: He's a stringy fucker.
Larry: I know who you are. I love you. I love everything about you that hurts.
Alice: So this man comes into the café today, and he says, "Hey waitress, what are you waiting for?"
Dan: Funny guy.
Alice: So I go, "I'm waiting for a man to come in here and fuck me sideways with a beautiful line like that."
Dan: So what did he ask for?
Alice: He asked for a cup of tea with two sugars.
Dan: I'm your stranger. Jump.
Dan: What's so great about the truth? Try lying for a change, it's the currency of the world.
Alice: No one will ever love you as much as I do. Why isn't love enough?
Larry: Of course she enjoyed it. As you know, she loves a guilty fuck.
Anna: Don't stop loving me. I can see it draining out of you. It's me, remember? It was a stupid thing to do and it meant nothing. If you love me enough, you'll forgive me.
Larry: But we're happy... Aren't we?
Alice: I don't want to lie. I can't tell the truth. So it's over.
Dan: I love you, and I need a piss.
Answer: I think it was because of the offer that Larry made to Anna. He promised that if they had sex one more time, he would leave her alone and never contact her again. The fact that he was willing to give her freedom, is what made her choose him. Dan was more "needy" and pushy, which is hypocritical, because he left Alice based on her being needy.
Dan left Anna after confronting her about sleeping with Larry for the divorce papers. Anna begged Dan to not stop loving her, to not leave her. Looks like Dan could not stand Anna after she slept with Larry so she went back to Larry since she never turned in the divorce papers.
But after the incident, Dan went to Larry's office and begged him to "let" Anna return to him.