Relationships have to be two-way streets of giving, taking and sharing in order to truly work. I say this not because I have any sort of experience, but because I have watched my parents for the last 23 years. They've been through a lot of the same stuff you described--health problems (my mother and father both), financial difficulties, and mental health problems related to past abuse (my mother's 2nd husband was a tool). But because they have the ability to give, take and share so well they've been able to make it work. I see how hard it is on my mother when she gives too much (like when my dad has to work long hours), and I see how hard it is on my father when he gives too much (like when he has to try and understand my mother's 5000 neuroses). But they're always able to return to moderation, which is what keeps their relationship healthy.
I wish you the best of luck in deciding what is best for you. You need to do what makes you happy in the long run. Sometimes acknowledging that fact and making the decision to support it is very hard. Just know that there are always people here willing to listen.
