My boyfriend cant always get an erection
I'm 19, almost 20, and my boyfriend just turned 19. We have been dating since March of this year, 2012, we are both we are both very attractive people(not trying to be arrogant) we usually have sex about 3 times a day but everyonce in a while He won't be able to get an erection or He can't keep one while were having sex. He says he's never been more attracted to someone like He is with me(which I honestly believe cause I've ssen all the otver girls he's slept with and I am the best looking, again not tryong to sound arrogant) and he's always in the mood but sometimes just can't get an erection, he always says its never happened to him before. He has had sex with 5 people including me but just started having sex the summer after his senior year in high-school(summer 2011). He smokes pot but usually only on weekends so I don't know if that has something to do with it but I am so confused and I need help please!!