Undeniable, but men deny it anyway. Some men just will not talk about sexual dysfunction, since so much of their identity as men depends on being a potent lover. In a case I knew personally (yes, men, we women talk about these things), the wife has great compassion for her husband because of the long hours he works and his general dissatisfaction with his life, but she's still very frustrated over his impotence and especially his not being willing to seek treatment. He won't talk about their problem and gets very uptight if she tries to; to him the fact that intercourse is over the moment it begins--if it ever begins in the first place--is not something he wants to face. He won't see a doctor about it; she's not interested in mechanical or other manipulation, and wouldn't think of going outside the marriage. If she brings it up at all (and I know this woman well--she would never put him down or be anything but gentle about it) he gets very embarrassed and acts as though she's attacked him.
I have no real counsel for her aside from trying to be her friend. She loves him dearly and will never divorce him over this or anything, but it's a real problem. I've been married about the same amount of time this couple has, and wouldn't be happy in a sexless relationship, either. What's a woman to do about such a super-sensitive husband?
And such a fellow is certainly no better than a woman who does such a thing. He might as well be a boy-brat, because he could either do something about it to please his wife, but he loves his own self-esteem more than her.
She just has to make a decision not to be an enabler for his insecurity. Sometimes being nice and sensitive just isn't the right thing to do. Of course she has to be careful not to destroy him, but she shouldn't let him be comfortable with the situation either.