You're finally giving her everything she's asked for, but it's too late." Another line directly from the script.
I heard all the same lines in your post, as I'm pretty sure most LBS's on this board have.
It's very hard after you've been close & intimate to have it followed up with pushing away & withdrawal, especially when they do it in a way so there will be no mis-understanding that they are not letting you back in.
I can't think of any positives to sending a letter to a WAS, only negatives....could just be me though. When in doubt......as they say, don't is prolly the way to go.