I'm going to lay a hard truth on you that you don't want to hear but you need to. If you can't deal with it because of your current issues with getting clean, come back to this post later when you're a little stronger.
Your wife is going to start fucking other dudes. It might not be tonight with her boss, it might not be next week, but eventually she's going to have another man. Shit, I bet there have been guys lined up waiting to take a stab at her and just see this as their opening. I'm sure all sorts of dudes, some I probably even hung out with prior, came out of the woodwork to show interest in my ex once we got separated.
If you guys are truly getting divorced, this is a reality you need to come to grips with. The hardest part, and ill have to deal with this too, is when another man comes in to your kids life.
The best thing you can do is not dwell on it and realize that you will be living separate lives soon. Your best get is to get clean and work on making you happy. It won't be easy on her either when you're slamming some younger piece if ass, but she decided to divorce you.
As I said earlier, she fell in love with you, and there is a possibility that once you get clean and take care of your demons things will work out, but you have to approach life like she's out the door because she's already got one foot out of it.
Get yourself a slam piece and realize you'll have to find live with another woman and it will happen once you find happiness.