I don't know if this is unusual or not, my fiance has trouble with either maintaining an erection and then coming too quickly. Sex often lasts five minutes or less, this has been going on for about eight or nine months, he had blood tests done last month and all came back normal so we are both puzzled as to whats going on. We are older but both inexperienced in relationships and sex. Any ideas what is going on, suggestions to what we can do to improve things?