Well the timing of this sure is not ideal for you and your M my friend!
I think you and your M are stronger than you know. If this ends up happening, I think you will handle it better than you think you will. You and H will definitely have to make a plan for how you will keep your M a priority.
Like rr I was wondering about the possibility of you moving with him if that job ends up looking like a good long term fit for him?