I am so sorry that you have to spend Christmas apart! This is my son's first deployment to Iraq (he's a Marine) and it's killing me...I know it's even harder in many ways to have a spouse gone.
Okay, as for the ring, you showed a lot of self-awareness when you said you see your wedding ring as him! I would suggest focusing on something else - a gift he gave you or your wedding picture or even your little girls as being him too. He's with you in their little faces and in your heart...I hope that gives you some comfort.
If I'm reading your tickers correctly, you have 2 little little ones -- talk about having your hands full! I admire you for being able to hold a family together and lose weight at the same time. And that ring will be back on your finger before you know it!!!!