So my questions:
1. Do I go to this program with her on Wednesday even though she is still dating this man? I asked her why she wanted to go and her response was “I am willing to try one step at a time to see what happens”
I think it's OK to go. But the focus should on listening and validating. That said, you cant really progress as a couple until it's the two of you committed to making things work.As long as OM is in the picture, that cant really happen.

2. Do I continue to try 180’s or try to be more affectionate?
These are definitely different questions. YES, you should be doing 180s. Stop the unproductive behaviors. That said, while there is an OM, your affection is only making the situation worse. Stop pursuing her.

3. Do I give her an ultimatum about her dating this man and if she continued I will see the divorce through in about 28 days?
You already filed. YOU get to decide whether or not to stop it. Dont give an ultimatum, because what if she stops it to get you to 'unfile' and then restarts it as soon as the ink is dry? YOU decide whether or not to stop it. EVen if it goes through, what does it really mean anyway?

4. It seems she is slowly becoming more in reality. She is self-admitted to not knowing what she wants and that since she has been with me since she was 17 she wants to “see what else is out there”.
Is this a question? To me, it sounds pretty typical. Let her see. The grass isnt greener.

5. I have agreed to have a vasectomy reversal and give her another baby
Are you going through with the surgery? If so, I wouldnt. This shouldnt be a way to 'get her back'. This is something you should do if you choose to once this situation is resolved.

6. Do I have my head burred in the sand and should wake up and g through with the divorce? I love her more than anything and still to this day I could forgive her for dating this other man currently.
Divorce or no, you need to re-connect with yourself. What is important to you? How can you become the best version of you possible? These are the things to focus on now, I think.