I was an atheist during my early teens, when I started doing it. But, even then, something struck me as peculiar and unnatural about the whole act. And I used to wonder about and mourn for the purity of childhood. But lust takes over your life and warps your mind, I fell into all kinds of perversions and fetishes. It’s shameful but it’s true. It became a habit and hard to control. I would try to abstain for many days because it felt so unnatural but would keep falling back. When I discovered Catholicism a few years ago, I realized the true horror of sin, and that’s when I fought against it as hard as I could. God gave me the grace to see how horrible a thing I was doing, and the guilt inside me finally forced me to give it up. I fell a couple times here and now, and it’s a battle you have to face everyday, dealing with impure thoughts, avoiding looking at women lustfully… but by the grace of God, now I’m pure and would rather die than sin against purity. You have to realize what you are doing, it’s a sin against yourself, you’re defiling your own body; it’s a sin against your spouse/future spouse, grave infidelity; and it’s a sin against God, who gave you life.
If you’re struggling, I suggest lots of corporal penance and prayer. You should have the will to rather beat yourself to death than sin. It’s tough, but you have to muster the courage. Like our Lord said, it’s better to lose your body than to have both your body and soul cast into hell. Good wishes, and keep praying for the grace to overcome.
), cold showers when tempted, etc., etc.