§ 144. Proof required. 1. In an action to annul a marriage, a final
judgment annulling the marriage shall not be rendered by default for
want of an appearance or pleading, or by consent, or upon a trial of an
issue, without proof of the facts upon which the allegation of nullity
is founded. Plaintiff shall prove that there has been no such
cohabitation between the parties as would bar a judgment except that in
an action under subdivision (c) of section one hundred forty the
plaintiff may prove instead that the mental illness still continues.

2. In any action, whether or not contested, brought to annul a
marriage, the declaration or confession of either party to the marriage
is not alone sufficient as proof, but other satisfactory evidence of the
facts must be produced.