I'm sick with guilt for what I did to our M, I know what I need to do to start to heal it, but I waver.
What do you need to do to start healing? Listening to your BW and leaving the org even though you have many good friends there seems a good start, but you're reluctant...so, you know what to do but are reluctant to do it? You are reluctant to save your marriage? You are reluctant to put your wife above others in your life????
For some reason I'm getting nit-picky with your wording...sorry about that...
Can we fix this? No. You can fix you. She can fix herself. You can't take responsibility for each others healing, and you can't do the work for anyone but yourself. So "we" can't fix this.
What will it be like if we R? It will be different than what you had, but hopefully better. It will take a few years of a lot of hard work on both your parts, but when you get to that point where you realize you haven't thought about what you did for a while, it's pretty cool.
What will it be like if we can't? I've seen situations where the BS thrives and the WS keeps falling even lower. I've seen the opposite. For yourself, if you can't R, you will be living with the knowledge that what you did was too much for your BS to take. You'll have to live with the knowledge that you destroyed your M. It will likely be a very lonely place for a while at least. Hopefully you'll find a way to heal. It sounds like you may choose your friends and the org over your BS, so maybe they'll help you feel better...
Am I strong enough to stick with it, to go through all the pain? It's a choice. It isn't really about strength more than it's about whether you have the ability to be honest with yourself. If it doesn't hurt, you aren't doing it right. Look at it another way...are you strong enough to be the person you were? You know, the one who cheated? That's the easy way out, to stay the same. The harder path is to really embrace the pain, look at it, and figure out where it all came from.
Will I do it again? If you don't think you're strong enough to face the pain, then yes, you will likely do it again. It's sort of like an addiction, especially an EA, and it is likely you'll have bumps in the road. The point is to do whatever you can to make sure you don't.
Am I that broken? Yes, but it sounds like you didn't know it. I get that. I had now idea how screwed up I was until I started working on things...
Why did I do it? If you do the work, you'll find your answer. Takes a lot of time. and the answer may not be what you expect/suspect.
How do I support my BW? You support her by taking responsibility for your own actions, by standing there while she is raging or yelling, by looking at her when she talks to you and keeping your mouth shut if anything that is about to come out of your mouth sounds the least bit defensive...You support her by working on yourself.