I'm sorry you are here, but you will be getting a lot of good advice from some great people, so listen and apply.
I know what you are talking about when you say how bad your W's actions are hurting you. When my W started her A she started spending money on new clothes to impress the OM. Knife to the heart. She removed her wedding rings. Another knife to the heart. She took down everything in the house that reminded her she was M to me, right down to the crystal clocks we received as a wedding gift. A third knife to the heart.
Everything she does regarding the A will hurt. The only way I have found to deal with it is to not think about it as much as possible.
When I discovered my W's A on Christmas Day last year, I started doing much of what you are right now and it didn't make me feel any better. I snooped. A lot. I looked at her planner, email, call logs, text logs. Anything I could to keep track of her contact with the OM. It only made me feel worse. I didn't start to really deal with the issues until I STOPPED snooping.
Believe me, I know it is difficult not snoop, but it is for your own good. Tracking her will only keep the sitch in the front of your mind and not allow you to focus on the rest of your life. Your Master's Thesis will be tough enough. Obsessing about your W will make it nearly impossible. I don't know if I could have done mine while thinking about my W's A.
Do yourself a favor and listen to your therapist. Only then will you be able to step back, get a clear picture of your sitch and figure out what your next move should be.
M: 25 T:33 Me: 48 W: 49 S24, D21, D18, D15, S8 All living at home while going to school A confirmed: 12-25-17 EA Definite PA Probable