Maria did not love Hermann...
All she ever did in the movie was flirt and have affairs with every man she came into contact with - She stopped "loving" him the moment she threw the sign she was carrying on her back under the train tracks. Hermann was only an "ideal" to her, a romantic proposition she envisaged, "Who" Hermann actually was as a person did not really matter to her - as, we know, they were only married for two days before he was enlisted.
Maria is a tormented individual, borderline psychotic (lack of empathy), never happy, never depressed. She is most likely Fassbinders synonym for the post-war Germany and the people's state of mind.
"Sure. It's been there a while, it's still got Anthony Eden's lipstick on the bottle."