I have a question: I been beating my penis for a long time, but now that I'm having sex I can't ejaculate, and I have a little anxiety. What can I do so I can ejaculate with my partner? Also before I have sex, I have a little ejaculation.
While the problem is solvable, and if this were a case of newly married man having trouble having sex with his wife, I would be very willing to work with you to solve the problem. However, you are involved in sin. "Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge" (Hebrews 13:4). You are committing fornication and because of that I can't help you improve your ability to sin.
So what do I need to do? Will this stop me from having kids, sir? What's the problem? Am I damaged?
You are not damaged. There is nothing physically wrong with you. You will be able to have children on day. My prayer, though, is that you stop trying to have children until after you get married. No method of "safe sex" is guaranteed to prevent pregnancy. Each only reduces the odds. So every time you put your penis in your girlfriend there is a risk that you will make her pregnant.
But the proper thing to do is stop having sex until you marry a woman.
The problem you are having is psychological. There are things you can do to overcome the problem, but I will wait to discuss that with you when you get close to your wedding day.
"Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived. Neither fornicators, nor idolaters, nor adulterers, nor homosexuals, nor sodomites, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners will inherit the kingdom of God" (I Corinthians 6:9-10).