Is he infertile?

One: the girls were on the pill.
Two: he wears briefs instead of boxers. Tight briefs ruins chances of fertility in men.
Three: he had a vasectomy(highly recommended if you don't want kids).
Four: The girls are infertile.
Five: somebody lied and never told anyone.
Six: The women know their bodies very well.
Seven: miscarriage. That really messes up a woman's body big time.
Eight: Either it was 90% oral or anal.
Nine: he lied.

I agree with Suave-Man. This doesn't mean he's infertile. Probably more like he's a lucky son of a *****. It's hard getting pregnant sometimes, and many couples will try numerous times even when they WANT to get pregnant. But mistakes happen all the time, and it's a dangerous line to walk. He might be infertile, but I think that he's just been getting lucky. Not a great approach to take, in my opinion.

Well judging from 3 women and there's billions, you can't say that he's unable to reproduce as 3 girls is not sufficient evidence. He could have been dealt some great cards and it just didn't click those 3 times. Is it uncommon? It's possible that this could happen, it really is. If you said he did it with 20 girls then I might say he's infertile. Bottom line, don't have unprotected sex with your ex and if you already have, then you just might get pregnant.

Those three girls could have been on the pill.

Maybe or he is just lucky. The time frame for a girl to get pregnant in the month is so small. Small I mean within a 5 day period. Either these 3 girls knew their cycle well or like you said he could be infertile.

He's probably just lucky - or it is possible that the girls he was with were on another birth control method. I dated my boyfriend for about 5 months before I learned that I was using the birth control pill, so it's possible that these girls just didn't tell him.