Proctor may have saved himself and his wife from being sentenced to death if he had gotten involved sooner. By waiting to act, Proctor allows the trials to gain momentum that proves impossible to reverse and he is ultimately caught up in that momentum and sentenced to death.
Proctor hoped to avoid becoming personally involved in the town's hysteria. He hoped to keep his personal life private also.
In order to save his wife from the sentence that awaits her for witchcraft in Act III, Proctor confesses to his affair with Abigail, making his private mistakes public. Had he acted sooner, he may have been able to avoid this step and maintain his reputation.
No true gains result for Proctor from his decision to temporarily avoid involvement in the trials, though he hoped that the town would recognize the girls' fraud and put a stop to the trials on their own.