We understand that you're going through a difficult time, but remember God promises to work all things together for good to those who love Him in Romans 8:28. First, let's pray together.
Almighty God, we come before You, lifting up our brother in his time of need. We pray that You will comfort him and guide him through this challenging situation. We ask that You will soften the heart of the young woman and help them both to understand Your will for their lives. Give them wisdom and discernment, and if it is Your will, restore their relationship and use it for Your glory.
However, let's remember God's Word in the book of 2 Corinthians 6:14, Do not be unequally yoked with unbelievers. For what fellowship has righteousness with lawlessness? And what communion has light with darkness?
First, it is important to know this young woman has accepted Jesus Christ as her Lord and savior. If not, we encourage you to share the Gospel with her and pray for her salvation. Then it is important to trust God's timing and plan for both of your lives. Do not try to force things to happen, refuse to change the plan of God to fit your desires. Remain in courtship with her but it is vital to resist any sexual contact before or outside marriage. It is equally important to refrain from any actions that that God has prohibited in his holy word.
In 1 Corinthians 7:39, A wife is bound by law as long as her husband lives; but if her husband is dead, she is at liberty to be married to whom she will, only in the Lord. And in Leviticus 18:22 You shall not lie with mankind, as with womankind. It is abomination.
Encourage one another to be a true follower of Jesus, to be seeking His will for their lives. This is not the time to be overly concerned about the physical attributes of a spouse but rather the spiritual attributes. We should be concerned with whether or not they are truly a Christian believer and are living their lives for Christ. In 1 Peter 3:3-4, Whose adorning let it not be that outward adorning of braiding the hair, and of wearing jewels of gold, or of putting on apparel; But let it be the hidden man of the heart, in that which is not corruptible, even the ornament of a meek and quiet spirit, which is in the sight of God of great price.
We also encourage you to examine your own heart and motives. Make sure that your love for this young woman is truly selfless and pure, as described in 1 Corinthians 13:4-7.
We pray this situation will bring you closer to God and that His will be done in your life and in the life of this young woman. Trust in the Lord 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. Proverbs 3:5-6.
Lastly, we noticed that you did not mention the name of Jesus in your prayer request. It is important to remember that it is only through Jesus that we have access to God. There is no other name by which we can be saved. As it says in John 14:6, Jesus said to him, I am the way, the truth, and the life. No one comes to the Father, except through me. And in Acts 4:12, There is salvation in none other, for neither is there any other name under heaven, that is given among men, wherein we must be saved.
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. 
