Hi,
A legal separation establishes that there is no longer the same community aspect of marriage from that point forward. Of course, any guidelines can be established that you both agree on, but basically it provides for each other's debts being separate from then on.
I would imagine that you are only considering this as a temporary measure to get medical stuff handled for a while. Even if you move forward with getting a divorce, it takes time, depending on when you two agree on settlement, and the time that it takes for the court to declare it. In the meantime, he is required to keep up the insurance that was in place.
Have you looked into COBRA? You should be entitled to purchase the same coverage for 18 months. I am going through a divorce myself, and I can really appreciate the concern over health insurance. I have many health issued requiring surgeries, and if I lost my insurance, it would cost me a exorbitant amount of money IF I could even get it. 18 months of COBRA might give you a chance to find insurance elsewhere (through an employer?).
I really understand your concern. That is why this presidential election is so important to me. I'm in a situation of having such high medical bills (even with insurance), that I have to choose between going to school, or paying for medical. I don't qualify for government medical assistance, but yet my medical costs are so high, that my income gets sucked up.
I don't know your health concerns, but another option might be to see a naturopathic doctor. I saw one who helped identify the imbalances in my body that were causing things like diabetes. My blood sugar is now normal, whereas regular MD's would have just had me on medication. Contact me if you'd like a referral for the naturopath that I used. He is in Santa Monica.
Do check into COBRA insurance through your husband's employer. It should allow you to continue coverage for 18 months.
All the best. M.