Medcare

I just turned 67 and you have been deducting $96.40 from my Social Security check every month. Why am I forced to pay this amount of money every month when I am covered under my husbands health insurance? I was told by a female representative from Social Security that it was a law and I had to let them deduct this money. Why, I don't need it at this time. I can use that $96.40 elsewhere.Thank You!