Leah, I'm going to get tough with you. I say the following because: I care for you, I want you to be happy, and I recognize some of myself in you. No judgment, just some tough love
I'm sorry about the complications, but I do suspect that you're doing something I've seen you do before: having expectations and approaching the situation with H from the perspective of a victim. You're very clearly feeling disappointment, and you're reacting to that disappointment in a way that is then changing the dynamic between the two of you.
You can't feel disappointed unless you had expectations. In that way, the disappointment you feel isn't on H. It's on you.
I know that you're a human being and this stuff is hard work. None of us are perfect. Your personal challenge is those pesky expectations, because they keep re-emerging!
The planning of the trip isn't something that you need to be involved in, is it? He's coming to see you, so let him worry about all of that that. And the circumstances (his work and the strange state of your M) mean that you might get late notice, so let's reframe all of this so that Leahsue is in her "happy GAL state", ok?
How about a different perspective where Leah comes first? She's off living her life and having fun, and her life does not currently involve rotating around an H who chose to step out on her.
Make plans, but picture H as no more than a possible addition to those plans, as opposed to a central feature. That way it doesn't matter if he's there or not, or if he gives you adequate notice or not. He also will get a peek into the fact that your life goes on without him, and that is a very attractive thing for him to witness.
H should be pursuing you in all ways. Putting yourself first allows him to do that. He knows he hurt you, and giving him any impression that he's still central in your life whenever he chooses is going to lower your perceived value. Really try and stop having expectations that he'll visit. Maybe he will! Maybe he won't! Either way, your life goes on, right?
So carry on with planning your life as is, and if he joins, that's great! If he doesn't, no skin off of your back.
If you can successfully adopt and communicate this attitude, it will have a nice side effect of lowering the pressure H feels. That will be a fantastic thing for the two of you.
Lower the stakes and make this a win/win for both of you, no matter what happens.
P.S. I would be slipping up in the exact same ways if I were in your situation! The frequent contact and the limbo state makes it so goshdarn tempting to develop expectations...
