Just before he defeats Voldemort, Harry brings Sirius back, Orpheus successful at last, but there is almost nothing left of the Sirius Remus remembers.
He knows he will never have Sirius, has made peace with it, and if he hasn't actually moved on, he's at least given up waiting for Sirius to come around and started to have a little fun on his own.
She freezes, not sure of what she’s seeing, as Sirius’s hand wraps around Remus’s ankle, brown fingers against brown skin barely visible in the brown grass, but Lily’s eyes are sharp.