I would say that most men like "the chase" but not all relationships are like that. I know people who have had sex on the first dat and have lasted for years. maybe you could bring it up to him about it casually to see his thoughts?
Everyone is different, so it is going to depend on the guy. If you're still seeing each other, then you weren't just a one night stand. If the relationship doesn't work out though, it doesn't necessarily mean that it's because you had sex right away. Just relax and enjoy the developing relationship
The grass is always greener on the other side...until you get closer and see that it's astroturf~