We are truly sorry to hear about the difficulties you're facing in your family situation. It's important to remember that God is our refuge and strength, a very present help in trouble. Psalm 46:1 We will pray for your situation and provide some biblical guidance.
Firstly, we want to address that the term "partner" is often used to describe a variety of relationships, but according to the Bible, a man and a woman should be married. They are to leave their own family and become one flesh, creating a new family. Genesis 2:24. We will pray that you will be married to a godly spouse, if this has not occurred already. It should be noted if the two of you are not married, then this should be addressed first and foremost. Referring to each other as a boyfriend or girlfriend should only be considered during the courting process where marriage is the final goal of this courtship. If this is not the goal, it would be fornication and a sin. Ephesians 5:5. If you are already married, then we will pray for your marriage to be strong and blessed by God.
Regarding the verbal attacks and accusations from the adult daughter, Jesus tells us in Matthew 5:44, "But I tell you, love your enemies, bless those who curse you, do good to those who hate you, and pray for those who mistreat you and persecute you,". It's a challenging command, but with God's grace, it's possible. Pray for her and ask God to soften her heart and bring peace to your family.
We will also pray for the well-being of the children. They need to live in a safe and loving home. Psalm 68:5 tells us, "A father of the fatherless, and a judge of the widows, is God in his holy habitation." God cares deeply for these children, and we trust Him to provide for them.
As for the court order and the placement of the children, we trust that the authorities have the children's best interests at heart. While we understand the adult daughter's unhappiness, it's crucial to remember that the well-being of the children is the priority. We pray that God will guide all parties involved to make the best decisions for the kids.
Finally, we want to encourage you to keep your focus on God. He is ultimately the one who can bring peace and resolution to this situation. Keep praying and trusting in Him. Proverbs 3:5-6, "Trust in Yahweh with all your heart, and don't lean on your own understanding. In all your ways acknowledge him, and he will make your paths straight."
Let's pray:
Dear Heavenly Father,
We come before You today, lifting up this family situation to You. We pray for the adult daughter, that You would soften her heart and bring peace to her words and actions. We also pray for the children, that You would protect them and provide for them a stable, loving home. We ask for Your guidance in this situation, that You would lead all parties involved to make the best decisions for the children. We also pray for this couple, that You would strengthen their relationship and guide them according to Your will. If they are not married we pray that they would marry, if they are married we pray that their marriage would be strong and blessed. And finally, we ask for Your peace and comfort to fill their hearts during this challenging time.
In Jesus' name, we pray. Amen.
Prayer Focus: God, Thank You. Thank You for loving me. God, I ask You in Jesus’ name bless me with everything that I stand in need of and everything You want me to have. Bless me to know You in truth, fall in love with You with all my heart, mind, soul, body, and strength and never fall out of love with You. Bless me to have an ever growing closer stronger, more intimate relationship with You. Bless me with the love, desire, strength, and the spirit of obedience to always delight myself in You, seek first Your kingdom, and Your righteousness. Help and strengthen me God to always respect and obey You. Bless me to trust You with all my heart, acknowledge You in all my ways, and lean not to my own understanding. 
