Actually, an ex classmate from college did this all the time with the girls he really liked.
If he just wanted to fuck the girl, he had no problem doing it in the first five minutes.
On the other hand, if she constituted girlfriend material for him, they would date continuously for over 6 months without having sex, because he didn't want to, he believed that doing that will ruin everything he accomplished that far and he was always looking at a 6 trial period, despite the girl almost begging for sex.
He's currently with the 3rd or 4th girl that went through the same process, and surprisingly, all of his relationships lasted for over 2-3 years.
But again, correlation is not causation.