I know it sounds bizarre, but if you can "let go," you have the ability to move in any direction.
I know I'm telling you this fully realizing that you are not ready to detach, but the sooner it happens, the better it is going to be for you.
You have to be able to drop the rope and show her you are ready to move on with your life AND you have to actually start to move on, not for her but for YOU!
Sometimes spouses come back, sometimes they leave, but I can sit here and honestly tell you that the sooner you make this process about you and becoming the person you want to be, the sooner you will find peace within your sitch.
See this as an opportunity to do the things you've always wanted to do. Go buy a new bike and start road tripping again. Find yourself. Set goals for you that you want to achieve.
This is what I will say about hope:
If you truly want to reconcile with your W, by all means leave the door open a crack, but it will do you no good to sit there and stare at the door waiting for it to open.
Understand that there is a very, very real chance that, despite what she led you to believe the last three years, the A never ended. In all honesty, brother, and I know this is a BIG, BIG 2X4 straight to the noggin, I'm going to tell you, with almost 100% certainty, that it didn't.
So here's how things play out now:
1) Your W has been cheating on you with one of your best friends for three years. Now you get to decided if you truly want her, or you just want her now because you aren't together. I want you to really look at the dysfunction that has taken place the last three years and decide if you want that back in your life.
2) WW and best friend AP have been carrying on this secret tryst for three years. They've created this little fantasy world where they will be together and everything will be happily ever after. I'll tell you this about hope: For as many times as you are saying that these sitches end in D, very, very rarely do WWs and APs end up working out. Chances are he's going to flake once the finality of the sitch gets real for him.
You are in complete control of what happens to you from here on out. Realize this and embrace it.
From my personal experience, I know that once I was ready to leave, things got better for me. I was able to set appropriate boundaries that protected (and still protect me to an extent) my well-being.
My WW ended up coming back, but I know that regardless of the outcome of my M, that I was going to be okay because I took care of myself first.
the 'Stones said it best:
"You can't always get what you want, but if you try sometimes, you just might find, you get what you need."
Carry on, brother. Be strong. Be you. Find yourself in this mess and things will work out the way they are supposed to.