The withdrawal method can work. The whole process is reliant on everything coming together (no pun intended) so it is actually designed to not work everytime. Of course the chances of getting someone pregnant are great enough I wouldn’t recommend it. Also, you seem to be worried about pregnancy, which is not a big deal, and not dangerous diseases associated with having unprotected sex.
My husband used the same method and we know that he doesn’t have any extra spawns running around out there (he stayed in contact with his ex-girlfriends for a while after they broke-up, specifically for that reason). Now with that said, we have a 3 1/2 year old and another on the way and they were both a ‘surprise’, so the method doesn’t always work.
It has been predicted that it is about 75% effective, and its more effective with some guys than others. I used it about two years ago and I have a 15 month old daughter. It didnt work for me. Have you ever heard of “precum”? That can get a gal pregnant too. I wouldnt rely on it as my only means of birth control, trust me I should know!
From Doc PeeDee:
Although this is an extremely risky birth control method, it does lessen the chance of getting pregnant because not nearly as many sperm actually get inside of the woman so the chances diminish. but it can always happen.