I don't really think I can say anything that will help you. But I'll give it a shot. This post is all about your tone for the last weeks, and reading between the lines. And you aren't going to like it.
You seem to be in some weird, egocentric place in which you can't see very far from what you want at a particular moment. You even seem to be telling yourself something like, "oh, I know this will hurt me and W and my R with her, but boys will be boys, and I'm just a poor little boy, can't help it, ha ha."
Can I just say this is a huge major YUCK.
As for the latest... "I did a slight slip yesterday. We were emailing back and forth about Christmas for the girls. At the end of one email, I just wrote "Love you" without thinking about it and hit send. Didn't realize until a few minutes later (been a lot frazzled with work). Exchanged a few additional emails, she didn't acknowledge it. I apologized for the slip."
FWIW, I don't buy this at all, and I doubt W does either. At this point, it doesn't even matter if it is true, given your general pattern of behavior. If I were her, i'd think you wrote the "love you" on purpose to get a reaction, to test the waters, whatever. When it didn't get the reaction you wanted, I'd think you tried yet again to get the reaction by "apologizing for the slip" which gives you another chance to point at the "love you" and say LOOK WHAT I DID, LOOK AT ME, GIVE ME ATTENTION, REACT, DO ANYTHING, I'M HERE, I'M HERE, I'M HERE. If I were her, I really can't imagine interpreting that as anything other than a manipulative, guilting stunt trying to get me to see YOUR light before the holidays. Not attactive.
W is not being immature. She does not want an R with you, so there is no need for her to work through a non-existent R with you. She does not owe you love. You are not entitled to her love. You are the one who keeps throwing tantrums in a million small ways.
As for the butt squeeze, this is about as attractive as the "accidental" tentative breast swipe during a back rub. If that makes no sense to you, I think its time for you to read GH's threads again, closely this time. I would not take "Mr. Whipple is dead," as a sign of encouragement, nor your W's pretty much ignoring it. I expect she takes a similar tactic with your kids -- ignoring unwelcome behavior so as not to inadvertently reward it and to help extinguish it by making it ineffective behavior.
I can't remember, did you start IC yet? If so, again, the whole W-violation incident could really use some introspection.
Quit trying to extract from W what she doesn't want to give. She doesn't want to share herself with you right now. She doesn't want you inserting yourself into her things (re the Thanksgiving volunteering debacle.) That is her thing. Quit trying to mark her space with your scent. It is NOT working for you at all. The more you do this, the less of an R you will have with W. Next time, she will not share her volunteering plans. She doesn't want your uninvited intrusions into her life. Again, getting a grip on the whole W-violation incident may help you get a grip on this dynamic.
But this is work for you to do ON YOURSELF, BY YOURSELF (except for IC, of course.)
One of your "little slips" is going to break your back soon.
Grow up. Be a man. Give W the space she has asked for. Quit acting as though she owes you anything. You aren't a victim in this. OM is NOT why W has a big problem with you. It is your words/actions/behaviors/sense of entitlement/victimhood that are repelling W.
All that being said, you are making progress.
This is great: "The urge to do so keeps popping up -- STRONGLY -- but with less frequency and, so far, I've managed to fight it down."
