On the first of December, we got married (3)
I believe the answer is:
wed
'married' is the definition.
(wed can mean married)
'on the first of december we' is the wordplay.
'on' means one lot of letters go next to another.
'the first of december' becomes 'd' (1st letter of 'december').
'd' after 'we' is 'WED'.
'got' acts as a link.
(Other definitions for wed that I've seen before include "Join" , "united" , "Married" , "Unite closely" , "Joined in the dew" .)