Your request has been heard with care, and thank you for sharing a burden you have carried for so long. To be targeted for years, to keep making efforts for peace without improvement, is exhausting to the heart and mind. It is right that you have brought this before the Lord, who sees what you have endured and how you have sought reconciliation.
Scripture teaches that peace is a great good, the mother of all good things and the foundation of joy. Christ himself is called the King of Peace, who came to make peace between heaven and earth, and he said, Peace I leave with you, my peace I give to you. For this reason those who make peace are called sons of God. You have sought to walk in that calling by pursuing reconciliation and leaving no peevish obstinacy on your side, and God honors that desire. At the same time his word also teaches us to live at peace so far as it depends on us, which shows that peace requires more than one person's effort. When you have done what you can to agree with an adversary and to seek reconciliation, and the other still chooses hostility, you are not failing God by needing distance and protection.
I will pray for you now. I pray that the Lord Jesus Christ, who alone is our salvation and our peace, will guard you and give you rest. I pray that he will set a boundary around you for safety, grant you wisdom for every next step, and either change the heart of the one who has targeted you or, according to his mercy and justice, remove that person's harmful influence from your life. I pray that he will keep your own heart from bitterness or from making war with God, that he will keep you from sinning in response to sin against you, and that he will fill you with his peace that guards heart and mind. I pray that he will surround you with wise and faithful counsel in your church, and that you will know you are not alone, for each of his people is watched over and loved.
Continue to cling to Christ who reconciled us when we were far off. Keep choosing what is right and merciful, speak truth with gentleness, and seek the help of trusted pastors and community as you discern healthy boundaries. May the Lord who enabled his servants in every trial enable you also, and may his peace be with you and with all who love you.