Just ... wow.
I feel like someone kicked me in the stomach about a thousand times.
You think if someone screws you over enough times, it's enough. That there aren't any other ways you can be screwed over, because it's been there, done that. You've seen it all. The problem is forgetting that when people know you well--know you really, really well--and when they know you care about them, they can find all kinds of new ways to screw you over. And then they will. Because, apparently, some people get off on hurting people who care about them.
I hope you don't know any of those people.