I discovered it feels good to say a few things once in a while to myself, and it might do the same for you other partners of survivors. Not that we don't love them or all that, or intend to stay with them through this, but it makes me feel free and that I'm making the choice to do so when I say these things:
I don't HAVE to save/help my survivor.
(for me personally, growing up) I don't HAVE to have my father's approval.
Infidelity doesn't HAVE to end my marriage.
(at the same time) I don't HAVE to stay married.
It feels good to tell myself these things over and over and even say them outloud. Because I think for me anyway, I've always felt I "have" to do certain things to "justify my existence" or to earn my place on this earth. I had strict parents who are perfectionistic and used a lot of "shoulds." My mom once even said to me, "What are you doing to justify your existence?" I know that Jesus loves me and that I don't have to justify my existence in any way.
So, for what it's worth, I like ranting on the "shoulds." It can free us up to make a true choice once in a while and not feel so out of control/powerless. I have the power to choose and it feels great to know I don't HAVE to do certain things, after all.
It were better for him that a millstone were hanged around his neck, and he cast into the sea, than that he should offend one of these little ones.