Hi,
I've been working in medical research for 10 years and have to do a lot of surgery... plus I'm starting med school this August with the intentions of becoming a surgeon... so I've dealt with this a lot. Yes, I always take off my ring to scrub and don my gloves... been married since 1999 and haven't lost it yet! I either slip it into my pocket or street shoe (good luck not noticing it when you go to put your shoes back on!) and when I'm in the regular OR, it goes on a chain around my neck.
It's not that I feel like I have to wear it to advertise my commitment (although I find it rather protective around some overworked residents!), but that I feel absolutely naked without it. If I take it off to shower and forget it... I often had that "I forgot something" feeling even if it takes me a while to figure out what it was I forgot! I think it's a comfort thing... I'm used ot it being there and out of sorts when it's not. (of course, in surgery, I am concentrating hard on the task at hand-- no pun intended-- so I don't notice it's not on).
And, hey, let's be honest here-- when you're working those long, hard days it's nice to look down at a ring (or a picture of your SO, or anything other symbol of your relationship) and remember that there is life outside of work and how wonderful and fortunate you are to have both!