Kim, what I observe from your sitch is that you really put pressure on your H. You pursue too much, I think. Asking him to define how he planned on breaking it off with the OW, repeating that a month is too long a time, not being satisfied by his answers so pushing for more, checking with him to see if he's yet spoken to the OW about ending the A, finally giving the ultimatum "who do you want?"... you knew they weren't the smartest things to do, yet you justified your reasons and progressively you saw your H go from feeling you two could work it out to getting angry with you to choosing the OW when handed your ultimatum. She even saw it coming from what she got out of her phone call with you.
Then there's the constant focus on the OW and analyzing what she's thinking and doing.
I agree with the others, you have to go dark - for your own sake. You need that to serve up some time and space to H, but more so, you need that to carve out some time to work on your ability to DB effectively if you're serious about changing these circumstances.
The key is to focus on your relationship with H, not on the OW. Think of him as a street cat that you're trying to get to eat out of your hand. You can't make threatening motions, you can't call out, you can't approach the cat. Instead, you have to sit still with food in your hand and make gentle cooing noises and let the cat come up to you. The cat comes up timidly to check it out, and any aggressive moves on your part will still scare it away. Even when the cat starts to eat out of your hand you have to move slowly and gently.
In other words, you have to push the positive buttons; you've been pushing the negative ones. Free your mind of trying to analyze the OW and H and keep those thoughts far away for they sabotage your actions and give you grief. That would be a good 180 all around, huh?
What could happen if you backed off like that and no longer pressed on H? H's likely to go along the path of least resistance. He's going to probably go to the person who hassles him less. That's why I guess he chose the OW for now. Use the contacts you have with him when he comes over for S9 to show him a happy benevolent you. Become the lesser hassle.
Think in terms of what words/actions on your part bring people together, and think this before you react to him. For example, he asked to chat with you. That's a yes or no question. Your answer, however, was in the form of an accusation/grudge ("is it worth us having a chat you have done nothing but lie to me"). That kind of answer doesn't bring people together, instead, it serves to create sides and defenses.
This is not a game. This is serious real life. If you want to attract H back, you have to get real serious about doing this.
