I agree that a second opinion would be a good idea. If the doctor doesn't agree with you having the surgery, it is possible that your insurance won't cover it either. Most of the time, insurance companies need documented proof that you have certain medical conditions, etc., and if your doc won't agree to it, it's unlikely that your insurance will approve it anyway.
I'd definitely seek another opinion if you think WLS is right for you!
Starting weight: 270