The amount of info that can be included in a few paragraphs is so little that all I have are questions, assumptions, and conditionals.
I'll start with why she cheated: Shirley Glass (NOT "Just Friends") states that affairs happen in good Ms when the WS lacks strong boundaries.
But IMO, the reasons don't really matter. No matter what the reasons were (in my W's case, self-hate). I had to deal with the grief, anger, fear, and shame that were dumped on me on d-day - and that was with a 4+ month A and a W who turned on a dime before she revealed her A. Those feelings seem to hit virtually all BSes, so they probably hit you. My reco is to work on processing those feelings out of your body.
*****
I, too, would like to know more about your WS's drinking. Is she addicted? If so, she'll continue to use, and alcohol does some nasty things to one's brain and other organs. If she continues to drink, no matter what she intends to do, the alcohol might remove exactly the inhibitions that you and she want to stay in place.
If she's an alcoholic, it looks like she's white-knuckling, and that doesn't have a great success rate.
If she's addicted to booze, She has to address the addiction before she can reliably address cheating.
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You have 2 episodes not very far apart. Were the new job and asshole boss enough to mess her up that badly? Is this the 1st time she abused alcohol on a sales trip? the first time she picked someone up?
IOW, I would question previous behavior. Your W might have a history of partying while away from home. If so, that might be a deal-killer.
(BTW, I know at least a few road warriors who abused alcohol without cheating, so one doesn't necessarily imply the other.)
*****
What do you want? Have you considered other options?
The fact is: you can heal with or without your WS. To R, you heal you; your WS heals themself; together you heal/build/rebuild/etc. your M - if you both really want to.
If you don't want to R, you're free not to. You can't make a free choice of one option unless you can also freely choose other options. My reco is: do not try to control the outcome. Focus on healing yourself, and let the outcome emerge from your thoughts, feelings, and behaviors and your W's.
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If you ask questions about the part you played in your W's decisions to cheat, you'll probably find that you played no part. 'Not taking care of yourself' is not a reason; everyone should know people gain weight as they age.
As alluded to above, my W did not like herself, so positive feedback from others (of which she got a lot, for good reasons) pushed her closer to the edge. She thought she was a terrible person, so she attempted to prove it. (That was one of several motivators.)
So IMO your W probably didn't do this to you. She did it to herself. Wanting external validation could be, for your W as for some others, is just the other side of the self-hate or self-disgust coin.
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It takes 2 to R and one to D.
IMO, taking responsibility for yourself and focusing on your healing and on what you want from your W is the best path for you to take. Look deep inside. I still wanted to spend my life with my W after d-day, and she was a good candidate for R, so I chose R.
Others wanted R, but their WSes were lousy candidates, and they D'ed. Still others realized they did not want to spend the rest of their lives with their WSes, and they chose D as soon after they realized that as possible.
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I also recommend asking questions of and raising your concerns to SIers. No one of us can legitimately tell you whether to D or R or wait - you know yourself, your WS, and your sitch better than anyone here does.
But you'll probably get a wide range of experience of what did and did not work for people, and that may provide guidance for you.