with my girlfriend for about a year, recently during
sex I
can stay erect for long periods of time but I just cannot finish. This seems to
ruin the mood for her, (even though I cannot understand the difference it would make for a female), Eventually I get tired lose concentration and lose it.
I was wondering is this a mental problem or a physical problem? She is a great looking girl, but I noticed it helps if I start thinking of other women.