I hope you can help me. I'm 20 years of age. I have never ejaculated in my life, not with sex or even by touching my penis. I get wet dreams often 2 to 3 times a month. I don't use a condom when having sex because I never cum. I get a full erection and very fast as normal, but I can have sex for hours and maintain my erection, but no ejaculation. I want children one day and hope there's something that can help me. I'm very worried about this.
There are two independent issues that you present.
The fact that you have wet dreams indicates that your seminal vesicles are operating and that the basic mechanism for ejaculating are in place. What you are experiencing is called "delayed ejaculation." There are a variety of possible causes, so the only way to deal with this problem is to see either your general doctor or an urologist. Most of the possible problems revolve around nerve damage due to birth defects, infections, or physical injury. Some questions: Do you experience orgasm? Do you produce pre-ejaculate fluid? Until the underlying cause is determined, it isn't possible to say what can be done about it.
Even though you currently don't worry about pregnancy, it doesn't mean what you are doing is right. Sex outside of marriage remains wrong, regardless of whether you can get a girl pregnant or not. See: Why Sex Outside of Marriage is Wrong. You are also taking huge risks regarding sexually transmitted diseases, since I assume you have been having sex with multiple women. These diseases are spread when the penis is in contact with another person's genitals, whether you ejaculate or not is not a factor. Many of these disease have little or no symptoms but can impact your ability to have children.