It's the stairway to heaven of breakup lines
Ted: I don't know what I'm gonna say. (Ted is struggling with how to break up with a girl)
Marshall: I'm not ready for a commitment.
Lily: Oh, that's such a cliché.
Marshall: It's not a cliché, it's a classic.
It's the stairway to heaven of breakup lines.
What does this sentence mean?
"It's the stairway to heaven of breakup lines."
(The 'of' here stumps me.)