I would argue that the best way to liberate women would be just to support them in choosing the type of relationship they prefer for themselves. I don’t know that monogamy OR polyamory is the right choice for everybody. Your significant other has chosen to be with you in the face of many choices, but that would be true whether she was polyamorous or not.
Polyamory also isn’t a cure for control. There are plenty of men out there who are (or claim to be) polyamorous, but try to install a one-penis-policy or act controlling over multiple partners at once.
There are animals out there who mate for life, I wonder if we would say that their relationships are all about ownership as well? Perhaps it’s just how their brains are made.