please advise

Stylical if you are a woman, why don't you start the good work, and marry your husband to 3 more? and stop pointing out the social benefits of multiple marriages or the need of multiple marriages to other people, with out first really trying hard to reap those benefits and fulfill the social need yourself...go a head.... let us know of your experience, after you have done this, meaning married your husband to 3 more women....
if you have not aldready done this , (for the reason that your husband doesn't want to marry other women, but u want him to), then i am afraid you are still not in a position to point to its need/benefits ....