When it rains it pours doesn't it. You should do whatever brings you the most peace, and peace of mind. What you have indicated is that any other method has not brought you any closer to being happy or having some sort of resolution, and that's what you really want. To me, NC is the only option you have. Believe me, you cannot reason with someone while in the middle of an A, they are not rational people at that point. The reason you are soliciting so many opinions is the same reason why half of us are on this sight, support.
NC is an enormous risk, and you are taking a leap of faith that things may get better. The only evidence to support it is how much better you felt when you were without her for a few days. I had a small meltdown from getting daily texts from my W about our family home, I called my mother for reassurance. I hold out hope that I can work things out with my W, but there are some other prospects I may consider as well, even if it's just an innocent lunch or the occasional phone call.
In my case, I did not send a NC letter, I just did it. The most recent time she came over and tried to start a conversation, I cordially shut it down and expressed my desire for her to head back home. She got the message and does to this day. I do not know how she feels, and I wonder about it a lot, but people are similar. If I miss her, and I do, I'm sure she does as well.
Now, I will say this, it takes a great amount of strength to do this. I had my little meltdown two weeks ago, and last week I had an anger attack that led me to burn a wedding picture in our backyard (I'm moving and if she hadn't messed up, we'd be doing this together jointly). It culminated with me driving past OM's house. That is where friends and family come in. I have a number of people who I can call if things get difficult. I also do things such as write out my feelings on paper or write a letter to her and never send it. Just remember that this situation is something you tell to understanding level headed friends. Tell only those people who are mature and rational enough to accept your decision, whether it be to end or reconcile the marriage. Otherwise, if you're fortunate enough to reconcile, outsiders will become an obstacle. I have that problem with my evil ass mother in law right now. Sorry.
One last thing, I'm in the same situation in terms of proximity, which is one of the reasons why I'm moving. Do whatever you have to do to avoid looking in the direction of that house. I generally avert my eyes so I don't know whether she's home, and that has worked well. But realize that such situations make things 30x harder.
Hang in there.