a man who impersonates someone else and rapes a woman--that is still rape. He did not have her explicit consent.
Her marital status has absolutely nothing to do with it. I get so sick and tired of rape being parsed to the nth degree... as if marital status diminishes the horrific impact of some man forcing himself on her. The question is: had she known the guy, would she have consented to have sex with him? Mostly likely, no. It's the same as raping a drugged person--she could not form consent because she was asleep and he did not identify his true identity.