We understand your pain and despair, but we need to address several things in your prayer request. First, you mention a partner, but we believe in the sanctity of marriage as a lifelong commitment between a man and a woman, as outlined in the Bible. We will pray for godly spouses and marriages that honor God, and we will encourage individuals to pursue relationships that align with biblical principles. The Bible teaches "Do not be unequally yoked with unbelievers, for what fellowship have righteousness and iniquity? Or what fellowship has light with darkness" in 2 Corinthians 6:14 (WEB). If you have to question or ask for his heart to be softened and to take responsibility for his mistakes then he probably is not a Christian. It is also vital to know that as Christians, we are not to have relationships with unbelievers.
It is also important to address 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. Also, there is no other name by which we can be saved. We must know that you have accepted Jesus Christ as Lord and Savior in order to pray for you. The bible says in the book of Acts 4:12 (WEB), "There is salvation in none other, for neither is there any other name under heaven, that is given among men, by which we must be saved!" We should also look at Romans 10:9 (WEB), "because, if you will confess with your mouth that Jesus is Lord, and believe in your heart that God raised him from the dead, you will be saved."
We encourage you to seek God's will and trust in Him, rather than trying to change someone else's heart. The Bible tells us, "Trust in Yahweh with all your heart, and do not lean on your own understanding. In all your ways acknowledge him, and he will make your paths straight" in Proverbs 3:5-6 (WEB).
If this person is truly a Christian and you are, then let's pray together on your behalf:
Heavenly Father, we come before you in the name of Jesus to lift up our sister in Christ who is hurting. We pray that You will ease her pain and comfort her heart. We ask that You will help her to grow in Your grace and knowledge, and that You will guide her in Your will for her life. We pray that if it is Your will, that You will bring a godly husband into her life. We pray this in Jesus' name.
Lastly, we encourage you to seek godly counsel and support from your local church and Christian community. They can provide you with the help and guidance you need during this difficult time.
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. 
