Bikingguy - You aren't rambling at all. I can really identify with how you feel.
Like you, my wife had a 15 year affair. I could have written something very similar to this post when I was about 9 months past d-day. I was 1,800 miles away from my family, working for an "indefinite" period of time, putting in six to seven 12-hour shifts a week. Our company had stress counselors on site, due to the stress of the job, and I was dealing with all of this on top of still trying to process the affair. The date that got me during that time wasn't an anniversary, it was my birthday.
A lot of times special dates, like birthdays, holidays, and especially anniversaries can be a really rough time when dealing with depression and pain from the affair, and it can be magnified through daily stress in what would normally be our ordinary lives.
A couple of months after my work trip, I really had to reach out and get some help for my depression. Please keep an eye on that. Try to treat yourself to as much as you can... whether it's a bike ride on your lunch, or a hoagy at your favorite sandwich shop... whatever makes you happy. If none of that works, there is no shame in seeking medical attention. That's what I had to do.
Regarding the anniversary - deal with that however you want to, and however you feel like. Be open and honest with your wife about how you feel about it now, versus a few months ago. There's also the option of going out and recognizing your anniversary, versus celebrating it. If you already have plans for a nice meal or something with your wife, you can always use that time to talk, reflect, and well, have a good meal.
Just wanted throw a couple ideas out there, but most of all I wanted to let you know that you are not alone in how you feel at this stage of your healing. I know that it sucks. I know that it hurts. You will get through it. Hang in there.
ETA: Looks like I cross posted with you. Wanted to let you know that I tried IC first, and that was a great deal of help to me. I ended up going on meds anyway, but the tools I learned in IC have helped me a great deal ever since going off the meds. Good luck.