Ruling on asking for a divorce from a husband who has some medical problems
Question

                My husband and i been married for the last 11 years and we could not have childrens due to my husband who had a medical  problems whimhich he knew of  but had hide it from me before we got married and had i knew than i woulden,t have got married to him and my question is. 

I want to divorce him and wanted to know what are my right?
Praise be to Allah.
    If the problems to which you refer have to do with some 
    defect in your husband that discourages intimacy between you, or prevents 
    achievement of the purposes of marriage such as mercy and love, because he 
    is not able to have intercourse or he suffers from a sickness which prevents 
    him from being intimate, then the scholars count these things as faults in 
    the marriage which entitle the wife to have the choice: in other words, you 
    have the right to annul the marriage contract or to leave it as is, and he 
    does not have the right to take any part of the mahr from you, because you 
    gained the right to the mahr in return for the intimacy that he has had with 
    you in past years. 

    With regard to the man’s sterility, i.e., his inability to 
    father children, this is not counted as a fault that would necessitate 
    annulment of the marriage, according to the majority of scholars, apart from 
    the view of al-Hasan al-Basri, and Shaykh al-Islam Ibn Taymiyah was also 
    inclined towards that view. 

    The husband should have explained his situation to his wife, 
    because the wife has the right to have children just as the husband does. 
    For this reason a husband is not permitted to practise ‘azl (coitus 
    interruptus) – which means ejaculating outside the vagina – without his 
    wife’s consent. 

    Ibn Qudaamah said, after listing the faults which give the 
    wife the option of annulling the marriage contract,  

    We do not know of any differing opinion among the scholars 
    concerning this matter, except that al-Hasan said: If one finds that the 
    other is sterile, there is the option of annulling the marriage. 

    Ahmad preferred that (the husband) should state his situation 
    and said: Perhaps his wife wants to have a child, and this should be 
    clarified at the beginning of the marriage. As for annulment, there is no 
    proof of that (in sharee’ah), otherwise it would apply in the case of women 
    when they reach menopause, and such a ruling is not known. For a man may not 
    have a child when he is young, then he may have a child when he is an old 
    man, or they may not have children at all.  

    With regard to other faults, according to the scholars it is 
    not proven that they are grounds for annulment. 

    (al-Mughni, 7/143) 

    On this basis, if you do not want to put up with him, then 
    either he should divorce you by talaaq according to sharee’ah, or you may 
    free yourself from him by khula’, whereby you agree to give him a certain 
    amount of money, or you return the mahr to him or whatever you agree upon, 
    whatever will be a suitable recompense in return for khula’, then he should 
    divorce you with a single talaaq. This talaaq will count as a revocable 
    divorce, and he will not have the right to take you back during the ‘iddah 
    or afterwards unless there is a new marriage contract that meets the 
    appropriate conditions. 

    The evidence that khula’ is permissible is the aayah 
    (interpretation of the meaning): 

    “The divorce is twice, after that, either you retain her on 
    reasonable terms or release her with kindness. And it is not lawful for you 
    (men) to take back (from your wives) any of your Mahr (bridal-money given by 
    the husband to his wife at the time of marriage) which you have given them, 
    except when both parties fear that they would be unable to keep the limits 
    ordained by Allaah (e.g. to deal with each other on a fair basis). Then if 
    you fear that they would not be able to keep the limits ordained by Allaah, 
    then there is no sin on either of them if she gives back (the Mahr or a part 
    of it) for her Al-Khul‘ (divorce). These are the limits ordained by Allaah, 
    so do not transgress them. And whoever transgresses the limits ordained by 
    Allaah, then such are the Zaalimoon (wrongdoers)” 
    [al-Baqarah 2:229] 

    The evidence from the Sunnah is the hadeeth narrated by al-Bukhaari 
    in his Saheeh (4867) from Ibn ‘Abbaas, in which it says that the wife 
    of Thaabit ibn Qays came to the Messenger of Allaah  (peace and 
    blessings of Allaah be upon him) and said, “O Messenger of Allaah, I do not 
    blame Thaabit ibn Qays for any defect in his character or his religious 
    commitment, but I would hate to commit an act of kufr when I am a Muslim.” 
    The Messenger of Allaah  (peace and blessings of Allaah be upon him) 
    said, “Will you give him back his garden [which he had given as mahr]?” She 
    said, “Yes.” The Messenger of Allaah  (peace and blessings of Allaah be 
    upon him) said (to Thaabit), “Accept the garden, and divorce her once.” 

    The scholars are agreed that khula’ is permissible if there 
    is a shar’i reason for it. For more information on the reasons, please see 
    question no. 1859. 

    We must advise you that if your husband’s character and 
    religious commitment are good, and there is no risk of you falling into 
    haraam things if you remain married to him, then it is better for you to be 
    patient and stay with your husband; perhaps Allaah will grant you from him 
    sons and daughters who will be the apple of your eye. 

    And Allaah knows best what is right. 

    See al-Mughni by Ibn Qudaamah, 7/246; al-Mawsoo’ah 
    al-Fiqhiyyah, 19/238, 240.