I hope you're doing better today. I know it feels like a sucker punch. I know it hurts but as someone else said nothing has changed. Rings/divorce papers etc are all worldly objects what matters is the feelings, the situation, the intangibles - they're no different than they were a week ago.
Think about what was going through his mind when he took it off and feel the anger and say to yoruself 'F him, all he's decided to do is cause me pain so why should I even bother with him right now...'.
Me: 35|WAW: 38|D: 6yo | http://tinyurl.com/2dxx7m6 Feb 2006, left, came back in two weeks Aug 2006, left again Apr 2007, filed for divorce Dec 2007, reunited Mar 2010, moved out, filed again