His wife cannot conceive now and he wants more children
Question

                About xxx years ago my wife underwent a hysterectomy to remove her reproductive organs.  She took this step by herself, under doctor's consent, because of complications with her ovaries and scarring.  I wanted to have more children with her, and now that we are Muslim, I want them even more in order to bring them up in the deen of Islam. I felt a deep sense of regret when she had her operation, but was hesitant to say anything because I did not want to worry her.  Later, after the operation, she changed.  She had many complications, and lost interest in me sexually. I still want more children, and I am getting older.  We have two -- one together, who is xxx, and a stepson, who is xxx.  The younger one has received Islamic instruction and accepts Islam as his religion, but the older one rejects it completely.  I love them all, but the situation saddens me.  I would like to start a new family, not discarding old one.  She prohibits me from another wife (but not in the contract), and I know she will leave me if I do.  My question is, what advice do you have to give me?  I love my wife, but I want to have more children, and my desire to be a father once again, raising my children in Islam is strong.  She also rejects adoption, even if it were halal. I am just looking for a way out of my dilemma.  Do you think my desire to start another family is halal? What does Islam suggest in this case?
Praise be to Allah.Your desire to form 
          another family is halaal, and your goal of having more children is perfectly 
          legitimate. Your wife does not have the right to object to that. If 
          she will leave you if you marry another woman, then she is a sinner. 
          Help her to bear with patience what Allaah has decreed for her, and 
          tell her that you will be fair and just as Allaah has commanded if you 
          marry another woman. Break though the barrier of fear and look for a 
          loving, fertile, religious woman, and pray Istikhaarah when you decide 
          to go ahead. Put your trust in Allaah, for whoever puts his trust in 
          Allaah, Allaah will be Sufficient for him. Be optimistic that Allaah 
          will relieve your distress and grant you ease after difficulty. Keep 
          calling the other son to Islam; may Allaah open his heart and guide 
          him at your hands. We ask Allaah to give you strength.