Lord help this child of yours, give her the strength and wisdom as to what to do. But also let her see that as you have forgiven us, so we have to forgive others. Maybe this is the opportunity she has to show her husband that you really have made in a change in her by being calm and not arguing nor try to defend herself. That if he wants to continue to believe the lies about her it's his problem not hers. That as long as she has a clean conscience and knows she is clean in your eyes she has nothing to worry about.
Also work in this man's heart and open his eyes to the truth Lord. Let him see she is a new creature in you and cleanse by the blood of the lamb. Bring a reconciliation into this marriage and depart from them all those evil minded people that have created so much trouble in this marriage Father, and are affecting this poor child negative. Let the father see that he should not allow anyone to mess with his son's mind not even him himself. Bind them with your love, forgiveness, understanding, kindness, trust, fidelity, and joy. Have them have a blessed Christmas and New Year together as a family again. May they make you Lord of their life, marriage , and be the parents their son disserves. May all these be done to Glorify You Heavenly Father, I ask and thank you in Jesus Precious Name, Amen!