longterm [M4F/Fu] The nice man and his terrible woman

The nicest guy in the workplace/on campus just got a girlfriend, she absolutely adores him and he obviously does too but something is off about her. It doesn't take long to realize she has been slowly changing him, some parts of his are better (physically, maybe more confident) then there are parts much worse (lacking empathy, crueler, and a lot rougher). Wonder if her influence will be for the better or for the worse and you can only wonder what she is changing behind closed doors~

(A basic corruption plot, I'm leaning to my character getting more dominant and mean but I'm with just about anything outside of feminization since I'm not really feeling that)