(((Brokenbride))) I'm just reading this and want to give you some encouragement.
I'm about 7 years ahead of where you are now, with a very similar story. Together over a decade, no kids, seemingly perfect marriage before, coworker affair out of nowhere, he was closer to my family than his, etc., etc. These unimaginative cheaters really do have a handbook. If you harness the wisdom of those of us who have gone before, you will save yourself mountains of pain.
First, you are doing amazingly well. When I was as early on as you are now, I was seriously contemplating suicide and barely able to function. You are doing so well, and you will continue to do better.
Try to go as No Contact as humanly possible. It's so hard; so, so hard, but it will help you in the end. You are so lucky that you don't have kids with him. I've had NC with my WXH since shortly after our divorce was final, and it's incredible. You will be able to heal much quicker since you can go true NC due to no kids. I told all my friends/family I didn't want to hear anything about him should they happen upon anything, and after a while, you really stop caring. But it is hard in the beginning. One of my favorite behavior change tricks is to visually show your progress and to reward yourself. I got a calendar and put a smiley face on every day that I didn't contact him. Then I gave myself a reward. One week = massage. Two weeks = 10 pack of yoga classes, etc. Whatever will be rewarding to you. NC is the single biggest thing that you can do for your healing. As much as it hurts, in the beginning, you will also want to distance yourself from his family and any mutual friends that are going to stay friends with him. As you heal, you may be able to rekindle those relationships, but for now you need to start fresh without constant reminders of what you thought you had and what you thought your future would be.
Focus on yourself. For me, I was socially isolated by WXH, so I had no friends. I joined some meetups (book club, beer club, knitting club), ran a lot, did yoga, took up painting, and started invited acquaintances out for a drink or coffee. I kept myself insanely busy and created a new social life for myself when I was 33. This has paid dividends beyond what I could have imagined.
Confide in friends. There is nothing to be ashamed of. When I was hiding the truth from family, I felt sick. But I told everyone. I was a fabulous wife who made a terrible choice of partner. I had just started a new job, and even told all of my new coworkers. Perhaps not the smartest move (probably depends on your work place) but for me, it was ideal. I had so much support and there was no gossip about my name change or why I was sometimes sad because I was upfront and people knew what was going on. Several people came to me to tell me that they'd been through something similar, and people were understanding when I had to take a day to go to court, etc. Invaluable.
Try to get the divorce over ASAP so you can focus on your life. It sounds like you are able to financially support yourself, and you'd likely not get much money from your WSTBXH. You can always make more money, but you can't make more time. Given your situation, it may be best to walk away and focus on your healing and your career. (I had put WXH through med school, to the tune of over $100k. My lawyer told me that my state's laws would look at that as a gift, so I had no claim to get repaid or to any of his future income, though I could take him probably up to the state supreme court and write new case law if I wanted to fight, but that it would be expensive and take time. I decided to let it go and focus on my career, which has paid off ten-fold, both in terms of promotions/raises I attained, as well as extra months where I could focus on healing instead of rehashing the unfairness of paying for schooling for a cheater and having to give him half of all assets even though he contributed far less than 10% during our 11 year marriage.)
I promise you that there is a wonderful life out there for you. You are smart, funny, and a real catch! Just focus on healing and getting better, finalize your divorce, and learn to recognize red flags. Become a whole, complete, interesting person on your own. I was single for about 4 years after D-Day and then met the most amazing man. We've been together about 3.5 years now, and our relationship is beyond what I ever could have imagined with WXH (remember, I thought my relationship with WXH was perfect and that I was super happy. If you'd told 2012 me that this was my future, I wouldn't have believed you as I still thought WXH was the most perfect partner for me and no one could even come close.) I know this will happen for you if you focus on NC, healing, and creating a wonderful life for you.
You've got this. It was NOTHING you did. Cheaters come up with ridiculous excuses so they can rationalize and live with their shitty life choices. WXH told me he had to cheat because I liked to read books and I saved for retirement. It's crazy making and don't waste anymore time trying to make sense out of nonsense. It does take 2-5 years to heal, so get started on that part so you can find your fun life that I know is out there. I benefited so much from the wisdom of those before me and while I definitely didn't follow all the advice 100%, listening to those on here got me healed far faster than I would have done on my own. You've got this!