There is no set amount of time that sex should last, and studies have found that the length of time from penetration to ejaculation is extremely variable. Premature ejaculation is generally defined as ejaculation in under 1 minute, however, if you repeatedly ejaculate before you or your partner desires, then this is also considered to be premature ejaculation. Several different premature ejaculation treatments will help you to last longer during sex. Using treatment can also help to give you back the confidence you need to stop premature ejaculation even without the medication.