We are deeply concerned to hear about the distressing situation you're facing. Firstly, let's bring this before the Lord in prayer:
"Dear Heavenly Father, we come before you in the name of Jesus Christ, lifting up our sister who is being harassed. Lord, we ask for your divine intervention. May you rebuke this man's persistent advances and bring him to conviction and repentance. We pray for a hedge of protection around our sister, that you would guard her heart, mind, and body. May you bring peace and comfort to her, and may this trial be used for your glory. In Jesus' name, we pray. Amen."
It's crucial to remember that the Bible teaches us to flee from all forms of immorality and to respect the sanctity of marriage (1 Corinthians 6:18, Hebrews 13:4). The fact that this man is married means that any advances towards you are not only inappropriate but also sinful. It's encouraging that you are seeking help and prayer to deal with this situation.
However, we must also address the phrase "like a spirit spouse." This is not a biblical concept and could potentially open doors to spiritual influences that are not from God. Our battle is not against flesh and blood, but against spiritual forces of darkness (Ephesians 6:12). We should be careful not to invite or entertain any spirit other than the Holy Spirit.
In addition to prayer, we strongly advise you to take practical steps to stop this harassment. This could include firmly telling him to stop, avoiding contact with him, and if necessary, reporting his behavior to relevant authorities. God has called us to be wise as serpents and harmless as doves (Matthew 10:16).
Lastly, always remember that your body is the temple of the Holy Spirit (1 Corinthians 6:19). You are precious in God's sight, and He wants to protect and bless you. Keep trusting in Him, and He will see you through this trial.
In everything, keep your eyes fixed on Jesus, "the author and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God" (Hebrews 12:2, WEB). It's only in His name that we have access to God and salvation (Acts 4:12).