Masturbation and Pornography

Q: I started pleasuring myself since I was 12. I didn't know what it was up until I was 13/14. It eventually turned into an addiction so bad that sometimes I did it in school. I tried really hard to get rid of this sinful habit by asking for Allah's help but eventually would slip into the sin. This sinful habit ruined my life, and I don't want it to ruin my life anymore. Also I've missed many prayers due to this sinful addiction. Am I supposed to make up those many prayers I missed? If yes, how should I do it.  Please give me advice on how to stop this addiction and please make du'a for me and for all brothers and sisters with issues whether it is the same issue as mine or not.

Q: I have a really bad habit of masturbation and I have tried so many different ways of stopping and I just can't. I am only 17 as well. Please help.

Q: Can you please list some of the punishments in the grave and jahannam for those who look at pornography or can you tell me a place where I can find this?

Q: If a person is masturbating and while he is doing he stops before he ejaculate will ghusl be waajib?

Q: I am a married man with kids. However, I have been addicted to porn and cyber sex. My wife doesn't know, but i feel I cheat her and also commit a grave sin. I have tried to stop and repent many times but after a break of a month or so I start again. I feel hopeless and fear marriage break up and later on hell in my after life. Knowing I have made gunah-e-kabeera and that I have back tracked after repenting, is there hope for me? What should I do to cleanse myself and be hopeful of paradise?