I have to disagree, somewhat, with what Whatisis told you...if she didn't have some feelings for you - she would have filed for divorce herself...she's still there.
IMO, she did it for a reaction...so react. Put her in the spot of explaining her need to take them off...at the very least, you will know where she stands.
You mentioned before, how high the divorce rate is in Sweden, that it's easy to do...why would she still be there?
She wants some reaction...change...
Whatis is right in suggesting that you focus on your life... but don't ignore the ring issue...it's one of her messages to you like the book and the note left for you to find.
Hey Luke, I agree with 1210 here. She hasnt filed, why? she plays games like this all the time with you, you ignore them and you allow her more and more justification for what she is doing. Call her out on it, let her know it is disturbing to you. Don't take it as anything more than a test.