Wow that sucks! I hope you're in an area that isn't fire a will and that he isn't the highest boss there is. Hopefully he has higher ups or an HR department that you can go to. If there is, than I bet they'd easily take your side. Question is whether you want to bother because once the girlfriend gets reassigned and you get your job back he may be a real pain in the butt to work for after all that. Hope you can find a better job elsewhere op. Plus, he'll figure out it wasn't his best idea once he realizes she can't do the job properly. Then he'll have to live with his mistake because he won't fire her. So the joke is really on him anyways.

This will end up biting your ex boss in the ass worse than it did you. You'll wind up with a much better job without an asshole boss hopefully.

Well if she is completely inadequate for the role, your boss is going to pay for it eventually. Hopefully you will find better.

I'm pretty sure he did it to keep getting laid. You deserve better than that anyway!

Wow, what an asshole. Talk to an HR and take that dick to court.

Maybe try contacting HR. I don't know much about work, but they could probably do something, no?

Did he outright say all of that? If he has a boss, I'd recommend going over his head.

Well for one thing it's illegal to do that so sue his ass and make millions

Is that even legal ?

I am sorry, but that is just unfair! It also sucks for the organization that OP works for, because clearly the that boss doesn't care..