If you mean to say she is biased based on the possible acquaintence of the two, only if you can prove the judge is not following the law. Remembr, judges have great latitude in matrimonial actions, however, if you can PROVE that she is not following the law, then you can appeal to the state bar, or state authority on the matter. I doubt that you would be successful in removing the judge from the case given the circumstances you indicate.
Bias is nothing new.
Don't worry about what you cannot control. Focus on what is legally relevant, not morally indignant or petty.