The Gem sounds bi-polar, I have a Gem that blew hot and cold until I left and now she chases me. The Aries sounds engaging and double fire... but the heart wants what it wants you know?
You gave the Gem your position. I don't know your history with her, but for her to throw out "liar" tells me you've had some misunderstandings or truth dodging back in the day... but toxic push-pulls aint where its at.
Give your Aries a chance if you aren't a field player and looking for a solid relationship. You might have to start blocking/ignoring the Gem, because "whoever cares least in the relationship controls it"...and it sounds like she's doing what she wants.