I was somewhat puzzled by your situation until I saw that you have survived abuse.
I am a survivor of abuse myself and I can tell you that it deeply affects even things you cannot see in yourself.
One of these things is the constant search for 'safety'. As a child you never felt 'secure' and you are seeking to find that both physically and emotionally as an adult.
That may be why you are so in love with a woman who is so far away and when you also have a committed relationship that (at least I gather from your post here) is not open to poly.
You may not be poly at all... (Not judging. Just raising the idea.) Possibly you are so in love with this other women BECUASE you CANNOT have her. She's 'safe'. You can love, share, feel, and hurt without ever having to perverbially 'pay the tab'.
I'm not calling you a cop out here. I'm simply saying that I've seen in my own life and in the lives of other abuse survivors a STRONG tendancy towards wanting only what they know they cannot reasonably have.
Before you consider pursuing thing with this other person any farther, you should ask yourself "If she were right here, right now, and I could have her completely with no hold backs or 'risk' to it, would I still want her?"
You might be surprised at the answer.
With all my heart I will love and not fail,
With all my soul I will fly and not fall.