If you are having sex unprotected, please be ready for all the responsibilities of parenthood. If you are ejaculating too fast, a condom will help with that.
Hey Sneaky, I am 51 years old and still have same problem if I have not had sex within last 2 days.
Now when I was 18 years old I had fast ejaculation but could quickly regain and erection many times so it wasn't quite as bad a problem.
But what I would do at age 18 was masturbate immediately before sex and then I wouldn't experience the fast ejaculation DURING sex. Get me?
Now at this age (51), that only works if I am in an extreme state of sexual excitement or else I cannot get a second erection for a while. Sometimes a LONG time.
Give that a try. Right before sex go in bathroom and masturbate. See if you then can last with your girlfriend. I bet you will be able to.