Why were St.s Zelie and Louis Martin canonized as a couple?

[Bernadette]

If marriage ends at death? I've never understood this.

[drummerboy]

Because of how they both lived their lives, which would include their holy, sacramental marriage which produced one of the greatest saints in Church history. Its what they do in this life that matters, not the state of matrimony afterwards.  Hope that helps   

[benedicite]

Why not? Sometimes we have martyrs canonized as a group.