Curfews can be lifted temporarily for reasons such as the death or serious illness (in hospital) of a close friend or relative or if it's really important that the detainee attend something outside his curfew.
I should think each case will be addressed on it's own merits and it won't be a blanket decision that if you get married, the curfew gets lifted.
Jack Straw only stepped in because Jack's prison governor refused to lift the curfew.
