How can one get rid of watching pornography and repeatedly committing masturbation, knowing that God sees, and what is the way to escape God's punishment after repeated repentance and relapse?

Your psychological pain from the repetition of sins is a positive sign that there is a sound part in your heart. The cure is to block every door that leads to sin or despair of God's mercy, for God forgives all sins, and replaces evil deeds with good ones for those who repent. And whoever repents from a sin is like one who has no sin. The pious are those who seek forgiveness for their sins and do not persist in them. Whoever repents with sincere repentance, then returns to sin and weakens, then repents again, is in a state of pardon, God willing. The Prophet, peace and blessings be upon him, said: "Indeed, a servant committed a sin and said: 'My Lord, I have sinned, so forgive me...' 'I have forgiven My servant.'" This is repeated three times, and its meaning is: As long as you sin and then repent, I have forgiven you.

Continue sincere repentance after every sin, and be regretful, and determined to abandon it. Strive to block the paths leading to sin, such as not being alone, drawing closer to family and wife if you are distant, constantly occupying yourself with beneficial work, and thinking about disconnecting from the internet or replacing your phone. Strengthen your faith by increasing your fear of God and being mindful of His observation of you, and recite the Qur'an frequently, perform supererogatory prayers, and supplicate for guidance.