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On the one hand, I don't want to give up on my marriage


And you don't have to.

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and find myself constantly rehearsing what I'm going to say when he comes to his senses and admits his mistake and willingness to come back.


Not sure why this should matter right now. This is one possibility for the future out of many, some of which you can't even imagine right now. Let the future take care of itself.

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On the other hand, I know I shouldn't get my hopes up


Agreed that you shouldn't get your hopes up about your M because you can't control what your H does. Nothing wrong with a healthy amount of hope for your future as an individual whether it includes H or not.

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and that I should move on.


Well you should definitely move forward in your life without pinning your decisions on his presence or commitment...that doesn't mean moving on from the M at this time unless you decide to end the M yourself or he starts the D process soon.