In Texas, do you have to prove to your employer you have other insurance if declining?

I have insurance through my husband's company. My employer says we need to fill out the enrollment form and check "reject" if we are not wanting their insurance. This form also says if you are rejecting, it wants the name, addresses and policy numbers of my health and dental insurance from my husband's company. This seems like invasion of privacy to me. Is this legal?
--------------------
Are you sure you're not misreading the form? Generally, the form would ask for the policy information of other coverage if you are *accepting* your employers coverage. Also, just some advice. Double check that rejecting won't cause problems with your husbands coverage - many health insurance policies require that a spouse or dependant child accept coverage if available through their own employment. You "might" find, if you read the small print, that if you reject coverage through your work, your husbands insurer may drop you. Richard
Source