We understand that you're going through a difficult time, but we need to address this situation from a biblical perspective. Firstly, it's important to remember that God's will should be our ultimate desire, and his will is good, acceptable and perfect.
Let's look at what the Bible says about relationships. In 2 Corinthians 6:14 WEB, it says, "Don't be unequally yoked with unbelievers, for what fellowship have righteousness and iniquity? Or what fellowship has light with darkness?" This verse emphasizes the importance of being in a relationship with someone who shares your faith in Jesus Christ.
Now, you mentioned that you want your ex-girlfriend back, but let's consider a few things. First, is she a believer in Jesus Christ? If not, then you should reconsider pursuing this relationship. Second, it's crucial to remember that God's design for relationships is for a man and a woman to come together in holy matrimony, that is a marriage covenant before God and man. If your desire is to be with her all day, that should be within the context of a God-honoring marriage. That is, assuming that you have prayed and are sure that this is God's will for your life. You should be seeking a God-honoring spouse.
Additionally, we want to remind you that it is only by the name of Jesus that we can be saved. If you have not already, you need to accept Jesus Christ as your Lord and Savior. Jesus said in John 14:6 WEB, "I am the way, the truth, and the life. No one comes to the Father, except through me."
Let's pray together:
Dear Heavenly Father, we come before you in the name of Jesus Christ, lifting up this dear one who is seeking your will for their life. Lord, we ask that you guide them in the path of righteousness and help them to desire a relationship that honors you. If it is your will for them to be with their ex-girlfriend, then we pray that you would make it clear and remove any obstacles. But, most importantly, I pray that you would give the guidance and that they would be obedient to your word.
We also pray for their ex-girlfriend, that you would draw her heart to you and bring her to a saving knowledge of Jesus Christ. We pray that you would work in both of their hearts and help them to seek you first.
In Jesus' name, we pray. Amen.