Can a man marry his aunt (mothers brothers wife)?

Q. My mother’s brother has divorced his wife who is also my age. I was considering marrying her after the Iddah period. Is it permissible for me to marry my mother’s brother’s ex-wife? Is it wrong to do so?

A. Your mother’s brother’s ex-wife is considered a non-Mahram (stranger) to you. As such, it is permissible for you to marry your mother’s brother’s ex-wife after the Iddah period. (Nisaa)

It is a different issue if you choose not do so for any other reason.