I'd ignore the whole bit about you being controlling here. A lot of the Poly People™ have a very clear and loving construct that they operate under, but it really only works when both people are party to it.
That's not your situation. You're trying to adopt a different set of parameters after the fact because that's what she wants. Your boundaries are simply you spelling out what you want — no shame in being clear and distinct with that. Your boundaries are also clearly mono-style boundaries. Again, that's what you entered into and wanted, so it kinda makes sense.
You're bearing all the fiscal responsibilities that allow her to live this whole duplicitous lifestyle. For what? Don't take a step back and let things breathe — take a step back and ask what you're getting out of this but heartache and a significant fiscal investment into a woman who feels it necessary to ride another guy and then lie about it?
You deserve better. I'm sure you could find it. Run, dude, run.