Joe Haldeman 
Forever War #4 [PDF ebook] 

Life on Earth is much harder and more confusing than either Marygay or William could have possibly imagined. Humanity has progressed in ways that seem barbaric and strange, and the two veterans must find their place in this new society, and conform to its norms or face the consequences.Faced with such an unpalatable choice, they realise they will never again be at home on the planet they were born on and head, once more, for the stars…