It seems he may be confused as to what he wants and when he wants it. Before he may have been feeling that you were trying to push him to be in a serious relationship and he wanted to take a few steps back before things got too serious and now he may realize that he liked you more than he thought he would, you met this really fantastic person. There is strong chemistry there and so you think this is it. You immediately put yourself out there and went a little overboard doing too many things to show him you were interested and when you thought it couldn't get any better, he said those dreaded words, "I need some space." You don't have to miss out on the relationship just because he needed some space it doesn't always mean the relationship is over. He wanted to make sure that this is what he wanted and you were who he wanted it with. I need some space doesn't always mean I am no longer attracted to you or the relationship is over. Sometimes when a person says "I need some space" all they are saying to you is that, at this time, he wanted to take things much slower. Many men hesitate because they fear that they might be making the wrong decision and will regret it later and he wants to make sure that you are the one. There is an old saying that "no one needs the needy" and desperate behavior is more likely to push him away. He felt that meeting your family was a bit too much and that you pushed them on him, they should only meet the family when you both decide that you want to take the relationship to the next level, so this time move at his pace and show him that you are ready to go as slow as he needs to go and that the ball is in his court.
I think his insecurities could stem from past relationships where he has fallen hard for someone and they had pushed them away and he is now afraid of being hurt again what you are going to have to do is show him that you are serious about the relationship and you don't want to hurt him. If he can realize that you aren't out to hurt him he may be able to opening up his heart to someone again. Taking the relationship slow and showing him that you want to be with him would be the best advice right now he wants to feel that he is in control of his feelings and with you he isn't sure.