Fox Gal,
Some cats are meant to be "only cats". That's just the way it is. No matter how hard you try. I would definitely try to re-home her. It's nothing you did or didn't do. Believe me.
I had a cat, his name was Tucker. He was a beautiful grey kitty who needed to be an only cat. He would terrorize my then kitty, Casey (RB, 2002). I wound up rehoming him with a couple who are my close friends. It was the best decision I ever made. Tucker, aka Otto, is now in a home all by himself with two people that love him dearly. I have never regretted my decision. Plus his humans give me frequent updates as to how he is doing, as well as giving me visitation (although I live in Michigan, which is 663 miles from Connecticut).
Good luck. Please keep us posted. We do care!
((((hugs))))
Donna
Bookmarks