Men's primary sense of sexual arousal is the visual. This is not the case with women. In my research on retarded ejaculation I have found that men who complain of a lack of sexual attraction to the partner and blame this for their RE tend to have a few things in common. A susceptibilty to anxiety, being easily stressed and having a very heightened visual sense and a high ability to get lost in fantasy. Many of these men are heavy porn users as pornography is a highly intense visual medium. They tend to create a "visual ideal" as to what arouses them and condition themselves to this ideal. The sexual dysfunction tends to arise when this visual ideal is not reproduced in the partner.
In a long term marriage the partner may have met certain arousal criteria for the man at the beginning of the relationship.. The way people look of course, changes as the years go by. A woman who may have been able to arouse her husband at the beginning of the marriage may lose this ability as time goes by. The stronger his conditioned visual preference is the more likely he is to suffer sexual dysfuntion over the long term. In non E.D. sexual dysfunction (R.E., Low Libido) married men most often blame a lack of sexual arousal as the cause.