Seems to me that your gf spends lots of time making her issues your issues--and you let her. It appears the most manipulation is coming from your gf. Is that something you're comfortable with on a long-term basis?
When speaking of various forms of non-monogamy...it ain't poly if you're just fucking around.
While polyamory, open relationships, and swinging are all distinctly different approaches to non-monogamy, they are not mutually exlusive. Folks can, and some do, engage in more than one of them at a time--and it's all good.