A man proposed to me while I am already married. What should I do?

You have certainly done the right thing. For a man to propose to a married woman is so disrespectful to her, and to her values, faith and morality. It is better to avoid such a person at all times. Indeed, it is not permissible to propose to a widow while she is in her waiting period which normally extends for four months and ten days. The maximum that one can do during this period is to hint at it, but no proposal may be made. How could a proposal be made to someone who is still married?