pitinmygut...I doubt that you could take your W off of your insurance even if you wanted to. You can't just take her off just because she left you, or at least, most health insurance plans would not allow that. You see, if that were the case, people could take their spouses on and off their insurance on a whim, and that just wouldn't be fair in many cases.
And besides, in your case, I don't see how that would really make any difference anyway. All it would do would be to tick her off. If you want her off your insurance, you are likely going to have to divorce her. Many plans won't even take off a spouse that is separated.
I think maybe you are just hurting and would like to hurt her back, but that type of thinking is going to backfire on you.
I could be wrong, but call your insurance carrier to find out.