The protagonist admitted to "leaving the door cracked" because hope is the last thing to die, even though they aren't even sure what the love they are looking for actually looks like anymore.
There is a heavy sense of lost time. He notes that even one more day of her presence barely matters compared to the vast amount of time he will spend missing her. #8 Spike - Nimic
He dismisses the idea of "remaining friends" as just another story people tell themselves to feel better about losing what they once had. The protagonist admitted to "leaving the door cracked"