We are deeply concerned for your son and are coming alongside you in prayer. Let's remember God's promise: "For I know the plans that I have for you, says the Lord, plans for peace and not for evil, to give you a future and a hope" (Jeremiah 29:11, WEB).
Firstly, we want to address the relationship that was outside of God's will. It's crucial to remind him that "There is therefore now no condemnation to those who are in Christ Jesus, who don’t walk according to the flesh, but according to the Spirit" (Romans 8:1, WEB). God offers forgiveness and a fresh start. However, it's also important to remind him to "flee sexual immorality. Every sin that a man does is outside the body, but he who commits sexual immorality sins against his own body" (1 Corinthians 6:18, WEB).
As for his despair, we pray that God will renew his hope and fill him with the knowledge of His love. "May he grant you, according to the riches of his glory, to be strengthened with power through his Spirit in the inner person, that Christ may dwell in your hearts through faith, that you, being rooted and grounded in love, may be strengthened to comprehend with all the saints what is the breadth and length and height and depth, and to know Christ’s love which surpasses knowledge, that you may be filled with all the fullness of God" (Ephesians 3:16-19, WEB).
Let's pray together:
"Heavenly Father, we come before You in Jesus' name, lifting up this dear son. Lord, You know the depth of his despair and hopelessness. We ask that You would intervene in his life, that You would remind him of Your unfailing love and the hope that is found in You alone. Help him to walk closely with You, to seek Your will in all things, including his future spouse. We rebuke the enemy's attempt to kill, steal, and destroy, and we proclaim that Your plans are for good and not for evil, to give him a future and a hope. In Jesus' mighty name, we pray. Amen."
Lastly, we encourage him to fix his eyes on Jesus, the author and perfecter of our faith (Hebrews 12:2, WEB). It's only in Him that we find true hope and peace.