If the guy actually knows anything about sex, he should already be aware that virgin p***y is tight. And tight p***y is the best. So if you want to keep him around and you're not stringing him along, tell him immediately. It won't make a difference to whether or not he wants to **** you, but at least he knows that you're being honest with him. If he works out that you're endlessly delaying the sex for no reason other than your own insecurities, I wouldn't blame him for dumping you and moving on. If you respect him enough and want to stay in a relationship with him, tell him and get the deed over and done with.