There would be no coverage. By definition in most policies, your spouse in considered a "Named Insured", even if her/his name is not on the policy. Regarding liability coverage, even if you are at fault, the liability coverage does not extend/cover yourself. Example would be, if you are liable in an accident and your spouse is hurt, you cant collect under your own liability policy. Same usually applies to children or blood relatives living in your household. Medical Payment coverage on a boat policy is usually "for others", not named insureds. Medical Payments is coverage for anyone injured regardless of fault/liability.
And yes I am an insurance broker........
Bob.