I had a vision in which I saw a man, whom I understood to be an Angel of God, erasing someone’s name from the Book of Life. I was made to understand that the reason for the removal was because of his involvement in viewing pornography.
I understood in the vision that it was not the first time the person’s name was removed from the Book of life. This gives me the understanding that a man can lose his salvation, and those whose names have been written in the Book of life can have their names removed from the Book of Life if they turn their back on the truth and live in sin.

https://youtu.be/S4yDqRIqP8Y
I also feel that the person’s name was not removed just because the person watched it once but it was a lifestyle of that person.
In another vision God revealed to me that the sin of pornography is a serious sin against God and that it is classified as idolatry.