Hi, im an 18 year old male....i lost my virginity when i was 13 years old, and never had a problem having sex until the last 2 or 3 years....I always want sex, but whilst i am with my partner, no matter how bad i want an erection, i can not do it. I have tried numerous things but can't figure out the problem! I have had sex numerous times, and now, due to some ungodly symptom of mine, i can't even get an erection while i am with a girl. Any time i am not with a girl, i can get an erection on command....but the second im with a partner, no matter how hard i try, nothing seems to work....Can anyone help me?!?!?!?!