Well, my name says it all...
It's always been a problem for me, off and on when I was young, becoming more consistent as I got older. Then I went on antidepressants for about six months, (about five years ago), and they ruined me maybe for good. My advice to anyone considering antidepressants is to try to avoid them if at all possible. No one even understands how they work, and there is an increasing body of evidence that they can have PERMANENT side effects. The doctors will largely poo-poo this because the pharmaceutical companies haven't done long term studies.
Now as to those who say "I wish I had that 'problem,'" think about it... Doesn't your partner get off on pleasing you, just as you get off on pleasing them? Personally, I have learned to live with infrequent orgasms during sex, but it has put a lot of stress on several relationships. My girl wants to feel desirable, wants to feel that she gets me hot, wants to see me lose myself in ecstasy, just as I love to see her lose herself in ecstasy. It is a real problem, and I haven't found a good solution.