How can one get rid of watching pornography, knowing that I pray and people see me as respectable?

One who falls into sin must repent with sincere repentance, and if they return to sin, they should repent again and not despair of Allah's mercy. They should adopt means of rectitude, such as associating with the righteous, frequently engaging in remembrance (dhikr), occupying themselves with what benefits them, and avoiding what leads to disobedience. They should strive against their soul and increase in supererogatory acts of worship, for good deeds erase bad deeds, and they should not despair of repentance. As for someone who prays at night and steals, it is mentioned in the hadith: "What you are doing will eventually deter him."