So I have been with my girlfriend for about a year, and having sex with her for about 8 months. Since we started having sex, it has never last a long time. I am always cumming way too fast. Sometimes it happens literally after seconds. I don't understand why. I try to take my mind off of it, but it just makes me remember what I am trying to take my mind off of, and I cum then. I haven't been able to have sex for longer than 10 minutes. It happens even if the last time I orgasmed was earlier that day. I wear a condom every time. I am not circumsized, could that be part of the problem? Thanks for the advice.