Nice-Guy Complex
The pattern of behavior in which a man slowly forfeits his masculinity to a woman believing that by empowering her, he is proving his love for her. This eventually creates a parasitic relationship in which the woman takes everything the guy does for granted and ultimately breaks his heart, leaving him an empty shell without the motivation to start over- the whole time never realizing why this keeps happening to him.
"I don't understand what I did to deserve this"

"You just suffer from the nice-guy complex"