Making it official

So this guy and I have been seeing eachother for a little over 2 months. We have gotten intimate a couple times now but we have not had sex yet. I kinda want to wait until we are officially in a relationship together... During a conversation he mentioned that he believes people should have sex before getting into a relationship with that person, he says that they'll know if that person is the one to get serious with after having sex. Like what if you get serious with someone before having sex and once you do, it's horrible and the chemistry is horrible.. So that's how he thinks about the topic. Ever since he mentioned that, I've been soo afraid of actually doing it with him ..