life ruin

My stepfather is a total loser, obese and lazy, a disgusting and unemployed couch potato. My mother kills herself working in another city to support her lazy husband at home. I always fight with him about it and end up insulting his appearance. I'm a handsome guy and I'm in good shape, but...

You've got a decent life. You've probably put a lot of work into improving things for yourself. You may even have other people relying on you. The idea of letting one person ruin all that to sate their sick desires is something that shouldn't appeal to you in the least. And yet... The thought...