They share a relationship and they were snogging on the Hogwarts Express in King's Cross Station. Both 19 year old Teddy Lupin and 17 year old Victoire Weasley have fathers who were attacked by the werewolf Fenrir Greyback. Victoire and Teddy are fourth cousins once removed, as both are distant descendants of Phineas Nigellus Black. Both Teddy and Victoire have mothers with unique traits related to their physical appearances; Fleur Delacour has Veela blood, and Nymphadora Tonks was a Metamorphmagus. Teddy is also a metamorphagus. Probably, they met "in family" because Teddy was treated like a family member being the godson of Harry Potter whose wife Ginny is part of the Weasley family.