§ 171. When divorce denied, although adultery proved. In either of the
following cases, the plaintiff is not entitled to a divorce, although
the adultery is established:

1. Where the offense was committed by the procurement or with the
connivance of the plaintiff.

2. Where the offense charged has been forgiven by the plaintiff. The
forgiveness may be proven, either affirmatively, or by the voluntary
cohabitation of the parties with the knowledge of the fact.

3. Where there has been no express forgiveness, and no voluntary
cohabitation of the parties, but the action was not commenced within
five years after the discovery by the plaintiff of the offense charged.

4. Where the plaintiff has also been guilty of adultery under such
circumstances that the defendant would have been entitled, if innocent,
to a divorce.