Again, that's all up to you. If you are really saying you can't do it, meaning you REALLY can't do it, then fine. If what you are saying is that you are REALLY sick of waiting for her and wish she'd just snap out of it, realizing what she has in you and your marriage and if she won't do that today, well, then that really SUCKS, then you have more work to do.
If you haven't figured it out yet, WE ALL ARE THE ONLY ONES WORKING ON OUR MARRIAGES around here. Does it suck, HELL YES IT SUCKS, but in the end, my personal philosophy is that I can either do this work with my W in my life, or without her. I value enough in "our" life to want to try to do it WITH her in it because failure to make it work will result in the "other" outcome anyway, so why not try?
If you truly feel like you don't want this anymore, then walk away. I happen to think you are more frustrated and angry than resolved and committed to ending things, and in that respect, you're not alone.
It has taken MANY people here getting to the point you're at, finally giving up, before REAL progress is made because that's the only way they can understand what detaching really means. Unfortunatly, they learn detachment right after they break things off with WAS "for good" and thus add another layer to their mess.
All I am trying to say is that if you want to walk away, just make sure that what you will be getting out of it is something you could not get before you walked away, realizing that getting a D will NOT end your relationship with her, or your feelings about what happened.