We understand your concern and will pray with you regarding your relationship. However, we must address some issues that seem contrary to biblical principles.
Firstly, the Bible teaches us, "Do not be unequally yoked with unbelievers. For what partnership can righteousness have with wickedness? Or what fellowship does light have with darkness?" (2 Corinthians 6:14 WEB). As followers of Christ, we should seek relationships with those who share our faith. You haven't mentioned if she is a believer, but this should be a primary consideration.
Infidelity and dishonesty are also against God's will. "You shall not commit adultery," and "You shall not give false testimony against your neighbor," are clear commandments (Exodus 20:14,16 WEB). If you believe she has been unfaithful, this is a serious matter that shouldn't be ignored.
Moreover, the Bible warns against being entangled with a contentious person. "It is better to dwell in a corner of the housetop, than to share a house with a contentious woman." (Proverbs 21:9 WEB). Her controlling behavior and deceitful actions are signs of a contentious spirit.
Let us pray for you:
Dear Heavenly Father, we come before you today to lift up our brother in his relationship struggle. Lord, we ask that you grant him discernment and wisdom in dealing with this situation. Help him to see clearly any signs of deception or manipulation. Guide him according to your will, and give him the strength to walk away if this relationship is not what you have planned for him.
Lord Jesus, we know that it is only through your name that we can be saved and have access to God. If our brother has not yet committed his life to you, we pray that he would do so now, surrendering his whole life, including his relationships, to your lordship.
In Jesus' name, we pray. Amen.
We strongly encourage you to seek God's will in this matter and be open to His leading. It's crucial to base your relationship decisions on biblical principles rather than emotions alone.