Nikaah & Marriage Issues

Getting married without one's parents consent if one fears falling into sin

Q: A person asked his parents to let him get married but his parents refused him even though that person was earning good and has enough money to afford all the expenses. That person was in fear of committing adultery. He asked his parents many times and even one day he told his parents the reason why he wanted to get married. His main reason of getting married was to stay away from haraam but his parents ignored him. He was very upset as his parents refused him. He contacted a few women in order to commit a sin but he immediately realized that he was about to make a huge mistake in his life and he repented and then refrained from committing such an act. He didn't committed zina. He stood steadfast and kept remembering Allah Almighty. He wanted to hide his sins and he wanted to confess only in front of Allah Almighty. What to do if the authority asks him as he didn't committed adultery physically? He's ashamed of talking to such women by text messages and he realized that it is a sin. He has already repented from it. What are the rulings of Islam as there was a talk of committing a sin but refrained and didn't committed it physically?

Seeking repentance for one's past sins before marriage

Q: If a man and woman commit zina before getting married. After their marriage, they had children and realized that what they have done before marriage was a sin. But they do not repent when being married because they dont have knowlegde that before marriage they had to repent.

After 6 years they got to know that they should have repented before nikaah, otherwise their nikaah is invalid. Is their nikaah valid or not as they repented after 6 years of marriage.