Even when Chibi doesn't remember Qilby he's drawn to him.
It's like some strange thread of fate binds them together, ties one's light to the other's dark, and he finds himself in each lifetime meeting Qilby's eyes and feeling like the world is right again just from their union. It does scare him a bit that Qilby can complete his sentences, but it all feels natural after a while, and they settle into their rhythm, work and leisure as a team, trading banter and kisses even after periods where they can't stand one another.
It feels like what any normal person would call "love," but he's always seen love as something ephemeral, something for a single life alone; when Qilby drags out his massive box of old diaries and he sees so much of his own name in entries from thousands of years ago, he tends to think it's something a bit more than "love."
When he tells Qilby this, the scientist just says it was the decision of the Krosmosz. Qilby doesn't believe in fate, only what he sees with his own eyes, and even the goddess Chibi sees clearly is just an abstract concept to him; but Qilby does believe in circumstances, and starting conditions, and universal forces, and those things he loops into the easy shorthand of "will."
Eventually, they stop thinking about it so much and go to sleep.