Marriage was the union of persons. It was usually made formal by a wedding service.
Donna Noble's marriage to Lance Bennett was prevented when the huon particles within her caused her to vanish while walking up the aisle. (TV: The Runaway Bride) She later married Shaun Temple and received a lottery ticket from the Tenth Doctor as a wedding present. (TV: The End of Time)
The Trickster arranged for Sarah Jane Smith to meet and fall in love with Peter Dalton. Once they were married, she would forget about defending the Earth and the Trickster could feed on the chaos. Peter revoked his deal with the Trickster, thus defeating it. (SJA: The Wedding of Sarah Jane Smith)