Anulling marriage when husband is impotent

Igros Moshe (E.H. 1:79) Impotent husband. Concerning a woman who married a man and immediately after the wedding it was clear that he was totally impotent and incapable of having sexual relations at all. It was also clear that  his problem existed prior to getting married since he was not able to have intercourse the night of the wedding. Furthermore there is the testimony of expert doctors who treated him with various medicine that were ineffectual that his condition is incurable and the wife is young and needs to remarry but her husband refused to divorce her and he ran away and it is impossible to obtain a get.  The question is whether the marriage can be annulled because if she had known that he was impotent she would never have married him?. This issue has been thoroughly discussed in contemporary and ancient  tshuvos. Some conclude that it is prohibited and some permit it theoretically but not in actuality. Others claim that it is permitted by the Torah but prohibited by the rabbis. However since this is an issue of helping an aguna the matter needs to be investigated despite the fact that I am not worthy in particular to decide between the words of our teachers. G-d should help us to not err in the halacha and we should teach the true actual halacha. It would seem clear and obvious  that if the husband is incapable of intercourse -which is the basis of sexuality and it is the reason why a woman marries and that the Torah describes the absence of intercourse as affliction (Yoma 77).  Tosfos (Kesubos 48) indicates that a woman marries in order to have sexual intercourse. Consequently it is clear and obvious that if the man is incapable of sexual intercourse that it is a very great defect in terms of the reason she got married and there is no need to bring proofs to this. But there is also a great proof as we see in the Ein Yitzchok (E.H. 24.6) in citing Tosfos (Yevamos 65) that if the husband is impotent he is required to divorce his wife.  This is also the view of the Tur and Shulchan Aruch (154) and also the Beis Yosef cites it in the name of Rashba that we force the impotent husband to divorce her since she got married to have sex. .  Thus we see it is a major deficit. So even if you have a doubt that perhaps there are some women who don’t care if their husband is impotent and therefore we can not force a divorce. But perhaps this last proof shows that we can force a divorce even though we are concerned that even though most women do care about this even though there is a minority that doesn’t care.  However it is more likely that the reason we can force a divorce is because all woman only marry for intercourse. And thus this is a case of mekach ta’us (mistaken transaction)to annul the marriage  The reason that they say to force the divorce and don’t say the marriage is annulled is because their case was of a man who became impotent after they got married. This distinction is important regarding all serious deficits, since there are some woman who prefer marriage under almost any circumstances.  Impotence is not only a major deficit but it is worse than a case such as mucha shechin (skin disease) because sex can not exist at all with it. All the Achronim agree that is a major defect and therefore it can be the basis to annul the marriage if she wasn’t aware of it before she got married and only learned of it after the marriage.  Consequently after much analysis in this case of an impotent husband and it has been determined that he was this way even prior to marriage and it is impossible to obtain a get from him – she should not be an aguna and she should be permitted to remarry because of annulling the marriage (kiddushei ta’os).