Stu - I am relatively new here and hesitate to respond to you as in the short time I've been a member I've seen and felt attacks towards LDW, of which I am one. However, you seem patient and reasonable and I will give it a shot.
First off, you sound much more patient than my H. We have a host of issues and stressors we are dealing with. However, I will say that your email would have caused me to tense up and withdraw further into my shell.
Your W may or may not be feeling an aversion to sex at the moment. I would suggest you sit down with her and say something like "our sex life seemed to be doing better (if this is true) but lately it seems to have fallen to the side again." Now...this is the important part...get off of the sex topic. "Is there something going on with you that is stressing you out or something I can help you with? Because I really want us to stay close."
I don't know if that makes any sense, but it's almost like when the aversion starts, bringing it up makes it a bigger issue. Where if you focus on the reasons it is starting - which may have nothing to do with you and your sex life - you will get further faster. That is how it works for me anyway.
When my H wants to talk, it is always and only about how unhappy he is with our sex life. I already feel like a failure, and that just makes it loom larger.
I don't know your history, but thought you might be interested in the reaction of a LDW to your email. It does sound like your W is avoiding the opportunity for sex...but the real questions is why.
FYI, we are currently following a plan that involves taking turns intiating. It takes pressure off of me, and it gives my H some control over when, how and where it happens.
Anyway, for the little I know about your situation, I've said enough. Good luck.