Is your insurance offered through your work? Are you still in open enrollment? Does she have the option to get insurance through her work? Is that still in open enrollment?
Usually, you can't make changes outside of open enrollment without a legal change in marital status.
I would consider dropping her from your insurance to be a jerk move unless it is part of a legal separation of finances.
Me: 44 H: 44 Kids: 20, 16, 16, and 10 Together/Married: 22 years H announced he was emotionally detached and considering D: 4/4/16 H announced he is going to try to stay and reconnect: 5/1/16