We are truly saddened to hear about the difficulties you are facing with your marriage and the challenges you are dealing with regarding your wife and her daughter. We will stand with you in prayer and speak God's truth into this situation.
Firstly, we must address that the Bible is clear about the sanctity of marriage. It is a lifelong commitment between a man and a woman, and divorce is not God's ideal plan Matthew 19:6. The Bible tells us that; "What therefore God has joined together, let no man separate."
However, we also recognize that there are times when separation may be necessary due to unrepentant sin and hardness of heart Matthew 19:8. It is clear from your request that your wife has been unfaithful and is seeking to harm you. Jesus himself said, "It was said, 'Whoever shall put away his wife, let him give her a writing of divorce.' But I tell you that whoever puts away his wife, except for the cause of sexual immorality, makes her an adulteress; and whoever marries her when she is put away commits adultery." Matthew 5:31-32
We must also address the fact that your wife has admitted to using you and not loving you. This is a form of deceit and manipulation, which is also sinful. The Bible tells us to put away falsehood and speak the truth to our neighbor Ephesians 4:25.
Regarding the behavior of your wife and her daughter, the Bible is clear that we are not to seek to harm others or take what is not rightfully ours. In Exodus 20:16-17, it states, "You shall not give false testimony against your neighbor. You shall not covet your neighbor's house. You shall not covet your neighbor's wife, nor his male servant, nor his female servant, nor his ox, nor his donkey, nor anything that is your neighbor's."
We must also rebuke the fact that you did not mention the name of Jesus Christ, Jesus, or Christ or an abbreviation such as IJN (In Jesus Name). It is only by the name of Jesus that we have access to God. The Bible tells us John 14:6-7, "Jesus said to him, 'I am the way, the truth, and the life. No one comes to the Father, except through me. If you had known me, you would have known my Father also. From now on, you know him, and have seen him.'"
Let us pray for you:
Heavenly Father, we come before you in the name of Jesus, lifting up our brother who is facing a very difficult situation. Lord, we ask that you would intervene and make it so these evil plans fail in Jesus name.
We pray that you would convict your brother's wife and her daughter of their sins and bring them to repentance. We also pray for your brother's protection, that you would shield him from the harm that is being sought against him.
We pray Father that your brother finds strength and comfort in you; that you would guide him through this difficult time and give him wisdom and discernment. We ask that you would surround him with godly counsel and support, and that he would ultimately find peace and justice in this situation.
We pray Father that you would bring about what is best for your brother in this situation whether this means restoration or separation. We ask that you would give your brother strength to endure this trial, regardless of the outcome, and that he would ultimately find his fulfillment and happiness in you.
We also pray Father that you would reveal yourself to your brother in a new and powerful way through this trial. Let him understand that you are the only way to salvation and that you alone can provide him with forgiveness, hope, and eternal life.
Finally, I pray Father that your brother's wife and her daughter find forgiveness, healing, and restoration in you as well. Let this situation ultimately bring glory to your name and further your kingdom.
We ask all these things in Jesus' name.
Finally, we encourage you to remain steadfast in prayer and the study of God's word. Trust in the Lord with all your heart, and do not lean on your own understanding Proverbs 3:5.
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. 
