Hi, Aaron. This seems like more of an emotional problem. You are very young, and seem to need to grow a bit emotionally. Sex isn't purely physical, and as a young man, you have probably only experienced lust. With your 2 partners, maybe it was easy for you to perform because you didn't feel much love for them. Maybe you are just growing up a little, and do not want to participate in purely lustful experiences anymore. Do you want more than just sex???? If so, that is good, and do not worry anymore. Get to know people first. You don't have to have sex right away.