He is attracted to a woman who is engaged to someone else
Question

                A friend of mine proposed marriage to a woman and they have seen one another within the limits prescribed in Islam, but they have not yet gotten married. I was intending to propose to her; I had asked about her, and I liked her and had become very attracted to her, but he beat me to it. I cannot forget this woman. I know that it is not permissible to propose to her when a Muslim brother has already proposed, as it says in the hadeeth. Will it solve the problem if I ask his permission to propose marriage to this woman, and explain my situation to him and get his permission?
Praise be to Allah. Yes, 
          that will solve the problem because it says in the saheeh hadeeth that 
          the Prophet SAWS (peace and blessings of Allaah be upon him) said: “None 
          of you should propose to a woman when his brother has already proposed, 
          until the first one gives up the idea of marrying her or gives him permission, 
          then he may propose to her.”
I 
          asked Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) about this 
          matter and this evidence, and his reply was in accordance with the apparent 
          meaning of the hadeeth.
(On this basis, if two men have proposed 
          to her then she should decide which of them she wants to marry)