Who's having the same trouble.
Peter is used to saying goodbye. It is not space that separates him; rather that insurmountable gap of time and age. For each farewell may mean infinity, each adieu the last exchange. He cannot sit on Wendy's window seat forever.
He's not deluding himself; Peter recognizes the signs. She's grown her hair, styled more for fashion than comfort. Her dresses hold her tighter, displaying curves that Peter knows (perhaps better than anyone) were not present before. She darkens the soft red of her mouth with lipstick, and a hint of rouge glows nicely on her cheeks in the dimmed night lights of the nursery.
Soon when he comes to the window, Michael will say, "Wendy doesn't live in the nursery anymore," and there will be no more stories.
But every night he tells himself is the last, making promises that he won't be back again. And yet he always finds himself perched on the window seat, ears pricked as Wendy inquires softly, "What story shall I tell tonight, boys?"
Nowadays John pretends not to listen, thinking himself too grown for such fancies. He instead scribbles pages and pages of schoolwork and annotates in his books. At the end of the night, when Michael is safely asleep in his bed and Wendy has gone to the armoire to tie her hair in its bedtime ribbon, John grasps Peter's hand in a shake and urges, "Let her outgrow you, Peter."
And he agrees yes, yes he will, for her own good. But then she returns, ponytail tickling his shoulders as she gives him a goodnight kiss. "Will you be back tomorrow?" She asks gently, her hand's weight pleasant and welcome on his arm. "I'll tell the one about Hook's hand and the crocodile, I think. It's such an adventure!"
Peter is confident that William, or Harry, or whatever boys have begun hanging around the house, have never saved Wendy from pirates, have never held her suspended in the air so that he doesn't have to share her with even the earth.
So he promises, "Of course," and John shakes his head, and Michael turns over in his sleep. But Wendy smiles, climbing beneath her covers in that graceful way of hers.
And he's gone, back to Neverland and the lost boys, back to Tink and Hook and Tiger Lily. And although he's hardened himself to the word, although he's grown used to its ruthless sting, he's never been able to tell her . . . "goodbye."