Your willingness to bring this struggle into the light is itself a work of grace, and I thank God for your love for Jesus and your desire to be free. To still struggle after giving your life to Christ does not mean you are abandoned, it means you are in the fight where God is forming you, and He hears your honest prayer.
Scripture is clear that lust is not satisfied by feeding it, but by turning from it. This desire is not quenched by adding more to it, but by taking away what fuels it and by convincing the heart that this path cannot give what it promises. When the mind is persuaded that this desire leads away from life and peace, the soul can begin to recover. That is why the call is not to manage the sin, but to flee from it, to cut off its sources, to guard the eyes and the heart, and to fill the mind with what is pure.
Remember also that those who once lived in sexual sin entered the kingdom not as they were, but as those who obeyed and believed and were purified and converted. God does not receive us because we remain as we were, but because He washes and changes us by His grace and righteousness. Your past falls do not define you if you continue to turn to Christ in repentance.
Growth in purity is often like building a house. The foundation must be allowed to set before more is added. Do not expect to become perfect in a moment, but receive the word portion by portion, let it settle in your heart, and build little by little in faithfulness. Small, steady obedience, prayer, Scripture, and accountability will make the whole structure strong.
Walk in humility before God, for He rests upon the meek and those who tremble at His word, while pride makes the heart unclean and open to the enemy. Bring your weakness to Him without excuse and without pride, confessing your need for His help each day.
I am praying for you now. Lord Jesus Christ, have mercy on Your servant who loves You and longs to be free. Forgive what has been done, cleanse the heart, and give strength to turn away from lust. Take away the love for what harms the soul, renew the mind by Your truth, and teach the steps of purity, faith, and self control. Guard the heart and eyes, provide a way of escape in every temptation, and surround this life with wise and faithful help. Make Your grace not only pardon but power to live anew. Amen.
Keep coming to Christ quickly when you fall, do not stay in shame, keep short accounts with Him, remove what causes you to stumble, seek a trusted mature believer to walk with you, and stay in the word and in prayer daily. God is faithful to complete the work He has begun in you.