I do not speak for other people who have faced the long illness of a loved one (and particularly a loved one who is meant to 'take care' of one - a parent, a guardian). Speaking only for myself, I find that on reflection, a huge part of this challenge is how it affects my sense of self.
In many respects, I consider myself a very decisive person. I know what I want, and I find a way to get what I want.
Not so when it comes to my relationship with my parents.
A normal part of 'growing up' is developing an independent sense of boundaries. This is difficult to do, but it's necessary and healthy. Our society seems to grant that it's a long and difficult process and grants people allowances for the many years of adolescence, during which time this 'coming into one's own' is meant to occur.
My adolescence was constrained, in many ways, by the fact of my father's illness. I see that now. Even though I was quite 'rebellious', and I did experiment and push boundaries and explore my interests, I was constantly aware of the limits. If I stayed out too late, or was in a belligerent mood, I felt guilty about what this would do my father, either directly or through the effect on my mother's mood. I don't think my parents ever explicitly constrained me by using guilt, but I felt it anyway. For the simple reason that whether they made me aware of a connection or not, I could see it myself. When my father was upset, or especially angry (as the parents of adolescents sometimes are!), he felt chest pain. There was no need to remind of this connection because it was exceptionally visible.
So I was split.
I was (and remain) quite strong-willed, and with diverse interests, and with a strong sense of adventure and fun.
But I was also relatively considerate and reasonable (compared to some of my less constrained peers).
Of course, this was a good thing at the time, but I start to wonder now whether I sometimes lose the balance between being considerate of my parents' needs and being aware of my own.
Sometimes I brush aside things I really want to do when I'm at home, because I imagine that I am needed there to help, to be a constant 'rock', to not impose any demands, to not express any desires.
Recognising this (on the threshold of 30 - late-onset anyone!?) feels like the first step towards becoming more than just a support for my father's illness (though of course that is important to me too). Towards becoming a person outside of that, and not just at the margins.