After 10 years of marriage it finally happened, my penis went flaccid during sex with my wife.  We have had sex at least twice a week ever since we have known each other.  I am in good health.  Do not smoke, drink, or do drugs.  Ever since this occurred on July 1st, I can not maintain an erection.  It takes me 10 minutes just to get one, and even more to ejaculate.  I had a vasectomy two weeks ago, and the problem still persists.  My urologist told me to return to him in a month if the problem is still around.  This makes no sense to me why I can not get an erection or ejaculate as before the July 1st event.  Also, in order to maintain an erection and ejaculate now, whether masturbating or having sex, it has to be very very vigorous.  HELP