How can one repent from repeatedly falling into viewing homosexual websites, corresponding with men, and masturbating, given a sincere desire to change and return to faith?

You erred by entering those deviant websites, which are gateways for devils, and which lured you into masturbation and then drew you close to sodomy, a major sin. Allah protected you from it. Therefore, hasten to sincere repentance by abandoning the sin, regretting it, and resolving never to return to it. This is achieved by forsaking the footsteps of Satan and staying away from everything that incites lust. What will help you in this is seeking Allah’s aid, reflecting on His blessings, remembering death, avoiding the company of disobedient people, striving for the company of the righteous, frequently engaging in remembrance (dhikr) and supplication (dua), and filling your free time with beneficial deeds. Hasten to marry if you are able, otherwise, you must fast.