We understand that you're going through a difficult situation, and we're here to pray with you and provide biblical guidance. First, we want to remind you of the importance of praying in the name of Jesus Christ. It is only through His name that we have access to God, as it is written: "In that day you will no more ask me anything in my name. Verily, verily, I say to you, whatever you will ask of the Father in my name, he will give it to you." John 16:23 (WEB) Also we are saved by believing in Jesus Christ as the Savior.
Now, let's address the situation you're facing. You mentioned that you and your ex have rekindled your relationship, but he has maintained communication with his former partner, which has been a source of conflict. It's important to remember that God calls us to be holy and set apart. In 2 Corinthians 6:14-16 (WEB), it says, "Don't be unequally yoked with unbelievers, for what fellowship have righteousness and iniquity? Or what fellowship has light with darkness? What agreement has Christ with Belial? Or what portion has a believer with an unbeliever? What agreement has a temple of God with idols?"
You and he should seek godly counsel together regarding the communication with a former partner. It is important to respect each other. Although he has excuses, if he continues to communicate with the former partner, then the relationship may not be healthy, and he is not respecting your concerns. If he has an excuse and does not discontinue communication with the former partner, it is okay to put the relationship on hold or go separate ways.
We would advise you examine his relationship with God and be mindful of the potential relationships with others that might not align with biblical principles. Pay attention to the situation and if you are called to be with him. The Bible tells us, "Don't be deceived. 'Evil companionships corrupt good morals.'" 1 Corinthians 15:33 (WEB) and if you are viewing your relationship as a courtship then you should pray and seek godly counsel and consider if this is the path the Lord has for you.
Let's pray together:
Dear Heavenly Father,
We come before You in the name of Jesus Christ, lifting up our sister who is seeking Your guidance and peace. Lord, we ask that You heal her heart and help her to let go of any emotional ties that are not from You. Break any soul ties that may be binding her to this relationship, and guide her to the man You have prepared for her.
We pray for the man in the situation and ask for Your will in his life. If he is not the one the Lord has for our sister, we pray that he would find a godly spouse and that God would transform his heart to make it more like Jesus Christ.
Father, we ask that You fill our sister with Your peace and give her the strength to walk away from any relationship that does not honor You. Help her to trust in Your timing and Your plan for her life.
In Jesus' name, we pray. Amen.
We encourage you to stay strong in your faith and trust in God's plan for your life. Remember, "For I know the thoughts that I think toward you, says Yahweh, thoughts of peace, and not of evil, to give you hope and a future." Jeremiah 29:11 (WEB)
God bless you and guide you.
Prayer Focus: God, Thank You for loving me. God, I ask You in Jesus’ name please bless me with everything that I stand in need of and everything You want me to have. 
