In view of Is it permissible for a gay man to marry a woman? question, is it permissible in Islamic views, for a man who cannot perform (for whatever reason), to marry?
In old Christian views, those marriages would be canceled (called "void", as if never have happened).
What is the Islamic view on that?
As of the tags, I'm not sure with the Arabic terms. Correct me it the tag is wrong or there are better or additional tags.
The ruling on marriage depends on the circumstances, marrying can be either obligatory, recommended, permissible, discouraged or forbidden. See Is it permitted to not get married?
As for a man who can not have coitus due to some reason (العنين) such as because of disease or old age or lack of sexual desire, or lack of interest in a certain woman etc. Then marriage is still permissible for him. Some have even stated that it is recommended.
من لا شهوة له، إما لأنه لم يخلق له شهوة كالعنين، أو كانت له شهوة فذهبت بكبر أو مرض ونحوه، ففيه وجهان؛ أحدهما، يستحب له النكاح؛ لعموم ما ذكرنا. والثانى، التخلى له أفضل
Those who have no desire, either because they were not created with any desire, such as one who is impotent, or they had desire but it has disappeared due to old age, sickness and so on. There are two opinions: First: It is recommended to get married because of the general meaning of what we have discussed. Second: It is better for him to remain single
The disposition of the man may change after marriage or his ailment may be cured. Or the couple might desire other benefits of marriage such as companionship, assistance, provision of accommodation and financial maintenance or intimacy other than intercourse etc.
However the wife should be informed and have agreed to it. That is because intercourse (at least once) is a right of the wife and can not be taken away from her against her will, see Sex deprivation: How long is it permissible for a husband to not have sex with his wife?. If the situation is not known and discovered later then the following can happen:
Whether a man can perform or not, he can know only after marriage because he would not have tried intercourse with another woman before as it is fornication, which is forbidden in Islam. Many consider masturbation as forbidden in Islam (I do not agree on this is true), so there is no way to know if he can perform or not before marriage.
After marriage if he cannot perform, he can try to treat his condition as there are number of treatments available now. He can consult with urologist or sexolist. If there is performance issue, the spouse should be supportive and should not blame husband as this will only make things worse. If there is fear in mind, problem will only increase. So take treatment and wait till things get improve.
As mentioned in comments, Marriage will still hold as long as Husband and wife is happy because there is no rule in Islam that intercourse should happen. There are only rules on when intercourse should not happen, like while in Hajj, during day time in Ramadhan etc.
