Much better You sound much less like a victim of circumstances now...
BTW, if it helps, I'd say you are just plain paranoid about the ring given all the facts. YOU BOUGHT HER ONE BEFORE??? There is no way that ring has anything to do with OM. IF ANYTHING, she is longing for times like those when you bought her the other ring, and, she might have even been trying to reach out to you in her own way by getting that ring. WAIT, I take it back. The Claddagh MAY have something to do with OM in that is a symbol IN HIS FACE that she is NOT with him but with you.
If you were more detached, rather than so reactive, then you might have even seen her getting that ring as a very sweet gesture. What if she had purchased a CD because it had one of your old songs on it, would you have assumed that also was about OM?
This brings be to: I said that I didn't know when to stop detaching and just go back to being a normal human being.
I have to recommend that you really read up on enmeshment issues. The fact is, if you were detached, you would be yourself and not sacrificing yourself to the drama and the R. You would feel like a normal human being. Detachment isn't something you do while your wife is boffing the neighbor, it is a healthy way to relate to people so you can offer them genuine love and compassion rather than filtering everything through your own needs and fears.