Do you believe that if you wait to have sex with someone you just started dating, there's a better chance of having a long term, meaningfull relationship?

I’ve heard this a lot especially coming from women. I’m not sure if I agree with it do to the fact that I started having sex with my boyfriend a short three weeks after we met and we’ve been together for almost three years now. How does waiting to have sex with someone help to have a better relationship with them? Granted, I’m not saying it’s okay to sleep around with every person you might have a connection with but seriously, how does that work? What do you guys think about this? Do you agree or disagree?