http://www.well.com/~aquarius/ellis-inversion.htm
"ATTITUDE TOWARD THE OPPOSITE SEX"
from Studies in the Psychology of Sex, pp. 278-279
by Henry Havelock Ellis
In 17 cases (of whom 5 are married and others purposing to marry) there is sexual attraction to both sexes, a condition formerly called psychosexual hermaphroditism, but now more usually bisexuality. In such cases, although there is pleasure and satisfaction in relationships with both sexes, there is usually a greater degree of satisfaction in connection with one sex. Most of the bisexual prefer their own sex. It is curiously rare to find a person, whether man or woman, who by choice exercises relations with both sexes and prefers the opposite sex. This would seem to indicate that the bisexual may really be inverts. 
In any case bisexuality merges imperceptibly into simple inversion. In at least 16 of 52 cases of simple inversion in men there has been connection with women, in some instances only once or twice, in others during several years, but it was always with an effort, or from a sense of duty and anxiety to be normal; they never experienced any real pleasure in the act, or sense of satisfaction after it. Four of these cases are married, but martial [sic] relationships usually ceased after a few years. At least four others were attracted to women when younger, but are not now; another once felt sexually attracted to a boyish woman, but never made any attempt to obtain any relationships with her; 3 or 4 others, again, have tried to have connection with women, but failed. The largest proportion of my cases have never had any sexual intimacy with the opposite sex,[1] and some of these experience what, in the case of the male ... 
[1] Hirschfeld also finds, among German inverts (Die Homosexualitaet, ch. iii), that the majority (though a smaller majority than I find in England and the United States) have not had intercourse with women; 53 per cent., he states, including a few married men, have never even attempted coitus, and over 50 per cent. are presumably impotent. The number of inverted women who have never had intercourse with men is still larger.
... invert, is sometimes called horror feminae. But, while woman as an object of sexual desire is in such cases disgusting to them, and it is usually difficult for a genuine invert to have connection with a woman except by setting up images of his own sex, for the most part inverts are capable of genuine friendships, irrespective of sex. 
It is, perhaps, not difficult to account for the horror - much stronger than that normally felt toward a person of the same sex - with which the invert often regards the sexual organs of persons of the opposite sex. It cannot be said that the sexual organs of either sex under the influence of sexual excitement are esthetically pleasing; they only become emotionally desirable through the parallel excitement of the beholder. When the absence of parallel excitement is accompanied in the beholder by the sense of unfamiliarity as in childhood, or by a neurotic hypersensitiveness, the conditions are present for the production of intense horror feminae or horror masculis, as the case may be. It is possible that, as Otto Rank argues in his interesting study, "Die Naktheit im Sage und Dichtung," [sic] this horror of the sexual organs of the opposite sex, to some extent felt even by normal people, is embodied in the Melusine type of legend.[1] 

[1] Otto Rank, Imago, Heft 3, 1913.