We understand your pain and disappointment, dear anonymous, and we are here to lift you up in prayer and counsel. However, we must address several issues in your request according to biblical principles.
Firstly, you mentioned that your partner is not a Christian and does not have a personal relationship with God. We are reminded in 2 Corinthians 6:14 (WEB), "Don’t be unequally yoked with unbelievers, for what fellowship have righteousness and iniquity? Or what communion has light with darkness?" While we can be friends with unbelievers, a romantic relationship with someone who does not share your faith can lead to many challenges and heartaches, as you are currently experiencing.
Secondly, your partner's behavior—cheating, pride, insensitivity, and egoism—does not align with God's will. We should pray for his salvation, that his heart may turn to God, but we cannot force him to change. It is crucial to seek God's will in this situation and ask for His guidance and protection.
Let us pray:
"Dear Heavenly Father, we come before You in Jesus' name, lifting up our dear sister who is in distress. Lord, we ask that You comfort her heart and give her the strength to face this difficult situation. We pray for her partner, that You would soften his heart and draw him to You, but Lord, we also ask that You give her the wisdom to discern Your will. If this relationship is not in line with Your plan for her life, we pray that You would give her the courage to let go and trust in Your goodness. Protect her, Father, from harm and heartache, and guide her steps according to Your will.
We also pray that she may know her value and worth in Christ. Remind her that she is fearfully and wonderfully made (Psalm 139:14), and that she deserves to be treated with love, kindness, and respect. Help her to find her identity and security in You, Lord, and not in this relationship.
In Jesus' name, we pray. Amen."
We encourage you to seek God wholeheartedly, trusting that He has the best plan for your life. The Bible tells us in Jeremiah 29:11 (WEB), "'For I know the plans that I have for you,' says Yahweh. 'Plans for peace, and not for evil, to give you hope and a future.'" Trust in Him, and He will guide your paths (Proverbs 3:5-6).
Lastly, we want to remind you that it is only through Jesus Christ that we have access to God. You ended your prayer correctly, "In Jesus' name. Amen." Continue to pray and believe in the power of Jesus' name.
Prayer Focus: God, Thank You for loving me. Thank You for loving me, Jesus. 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, soul, mind, 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. 
