We are glad to hear that you and your fiance are working things out, and we commend you for your desire to live according to God's will. You are right to feel convicted about engaging in sexual activity outside of marriage, as it is clearly addressed in God's Word. Let us first address the issue of salvation and then the issue of sexual immorality.
For God says,
"For I desire mercy, and not sacrifice; and the knowledge of God more than burnt offerings."
Hosea 6:6 WEB
But it is only in Jesus name that we have access to God.
"Jesus said to him, I am the way, the truth, and the life. No one comes to the Father, except through me."
John 14:6 WEB
Please make sure you and your boyfriend are both believers. Without belief in Jesus Christ, your behavior modification will be legalism. With belief in Jesus, your changes will be a result of obedience. To be saved, you must repent and believe on the Lord Jesus Christ. To be saved means to be born again as a new person in Christ. Jesus said you must be born again to see the Kingdom of God. Repentance is changing your mind and direction, changing your mind about Jesus and changing your direction away from your life of sin and towards God. Believing is trusting in Jesus for your salvation. Repenting and believing is something you can do at any time. To become a new Christian you must repent and believe the Gospel.
The Scripture clearly states "For this is the will of God: your sanctification, that you abstain from sexual immorality, that each one of you know how to possess himself of his own vessel in sanctification and honor, not in the passion of lust, even as the Gentiles who don't know God; and that no man should take advantage of and wrong his brother in this matter, because the Lord is an avenger in all these things, as also we forewarned you and testified. For God called us not for uncleanness, but in sanctification."
1 Thessalonians 4:3-7 WEB
Sexual intimacy is a gift from God, designed to be enjoyed within the boundaries of marriage between a man and a woman. Engaging in sexual activity outside of this context is sinful and harmful to your relationship with God and each other. God said,
"Marriage is to be held in honor among all, and the bed undefiled: but God will judge the sexually immoral and adulterers."
Hebrews 13:4 WEB Regarding marriage, the Bible tells us,
"Let marriage be held in honor among all, and let the marriage bed be undefiled; for God will judge the sexually immoral and adulterous." Hebrews 13:4 WEB
We understand your concerns and fears about discussing this with your fiance, but it is crucial to trust that God will provide the strength and wisdom needed for this conversation. It is more important to obey God than to fear losing your relationship with your fiance. Remember,
"Therefore do not be anxious, saying, 'What will we eat?' or 'What will we drink?' or 'With what will we be clothed?' For the Gentiles seek after all these things, and your heavenly Father knows that you need them all. But seek first God's Kingdom, and his righteousness; and all these things will be given to you as well." Matthew 6:31-33 WEB
Pray that God will give both you and your fiance the grace to stand firm against temptation and the courage to live in obedience to His Word, even if it means facing difficult conversations or decisions. As you both grow closer to Christ and commit to living according to His will, your relationship will be strengthened and blessed.
Let us pray together,
Dear Heavenly Father,
We come before You, lifting up this couple in prayer. We thank You for bringing them back together and for the conviction they feel to live according to Your will. We ask for Your forgiveness for the times they have fallen into sexual sin, and we pray that You would give them the strength and grace to resist temptation and live in obedience to Your Word.
Lord, we pray that you would work in the heart of the fiance, that he would feel conviction for his lust and desire to live righteously for You. We ask that You would guide them to a church where they can grow together in faith and be surrounded by a supportive community of believers.
Help them to trust in Your goodness and provision, even as they navigate difficult conversations and decisions. Give them wisdom and discernment as they seek to honor You in their relationship, and draw them ever closer to Yourself.
In Jesus' name, we pray. Amen.
We encourage you both to continue seeking God's will for your lives and to trust in His goodness and provision. Remember that His ways are always best, and He desires for you to live in holiness and righteousness. As you walk in obedience to His Word, you will experience the fullness of His blessings and the joy of a right relationship with Him.
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. 
