Well, the short answer to your question is, "I think you made a mistake".
I don't know the motive for your H's call (guilt, holiday sadness, missing your voice...who knows), but it was an opportunity to put the LRT and DBing into practice. IMHO, I think you should have left it alone and you would have been better off doing so. He did not ask for a response from you, did not ask a question, and did not create a situation in which you *had* to call him back.
The LRT accomplishes two things. First, it gets you away from your WAS so they can focus on what they've done, the problems in the M, and their role in the disintegration of the R instead of focusing on you. Second, it gets you away from your WAS so you can focus on your life a bit and disengage long enough to look at things from a more objective standpoint.
This was a good opportunity for both that you appear to have completely missed. While it is legitimate to wonder what it was all about, right now that is something for these boards or a counselor...*not* your WAH. I think you would have been far better served by letting your H contemplate his thoughts without interference and to recognize for yourself the fact he is, in some small way, missing you and noticing you haven't contacted him recently. I think most here would agree that this was a positive development.
Still, a missed opportunity isn't terrible, but bringing up your letter was. Forgive me for saying this, but did you temporarily lose your mind? Demanding an acknowledgement (and that *is* what you were doing) to your letter only confirmed what your H was already thinking as a result of the letter itself...namely that you're demanding!
By presenting him with this challenge, you took the spotlight off his missing you (or whatever it was that prompted his action) and put it squarely back on you and how you are demanding (as he sees it). I can't believe this is what you were hoping to accomplish.
You said: "I was hoping to discuss our situation further."
Given where your sitch is right now, this should be the *last* thing on your to do list. Discussing your sitch, R, M, or any related topic is not going to be productive or get you closer to saving anything at this point.
You said: "Since then, I've really been PO'd! Now, he's toying with my emotions. How dare he tell me that he's going to call, and he doesn't!
I don't know if your H is effectively toying with your emotions, but I'd bet that even if what he's doing qualifies as toying, it's not necessarily malicious (and you have no evidence that it is). He contacted you, you called him back, made him uncomfortable, and challenged him. He didn't want more of that so he made an excuse to end the call and didn't call back. I don't think that response is too difficult to understand.
You said: "At first, I didn't think he had someone else, but I think he does now."
You may be right. A WAS often (but not always) has something going on with someone else. However, I don't see anything in what you related that would lead me to believe this to any greater or lesser extent now than a couple weeks ago. What I'm trying to say is that if you didn't believe this to be the case then, I don't think you have any clearer evidence now to support a change in that belief.
This is the place to vent your frustration and anger. But I fear that it is coming out in what few exchanges you do have with your WAH. That doesn't mean you don't deserve to be angry, hurt, bitter, etc. But if you want to make progress, you're going to have to come to terms with these emotions.
Please note that your feelings are valid and I'm not suggesting you sweep them under the rug for eternity. But there is a better time and context to address them and it sounds like you need to be in a better place yourself before you attempt to do so. I hope you will continue to disengage from your H and recommit to the LRT. I believe it is your best hope.
OK, let me crawl down from my soapbox. I'm sorry you're feeling bad and hope the coming days are better for you. As for my sitch, I'll post a separate item.
