Dear Friend,
as per my knowledge, there is no separate policy for marriage leave. you have to check employee leave credit, based on that you have to calculate.
For Example 'A' is having 10 leaves in his account, he applied for leave of 30 days, total loss of paid days for that month will be 20 days, paid days will be 10 days.
Note: you have to follow your company policies, based on that you have to calculate.
with regards,
Ramesh.V
Sr.Hr.Executive