Netsy, some great advice and suggestions above and I echo everyone else in that you should just get on with it, and do your best to keep that Guilt Monster at bay. Do you need the special TP pointy stick, to poke it in the eye with? Someone here will pass it to you!
My mother was not like some I've read about here on TP (no child abuse), but was also not exactly the world's best mum, and we were never close. I'm an only child and have power of attorney, and now I am in charge and responsible for her, whether I like it or not (and I don't like it one bit). She was unpleasant to me at times, as an adult, and she was certainly difficult, challenging, and frustrating. To be honest, I mostly avoided her, until she started to have problems with what I now know, was the early stages of her dementia.
I struggled at lot with her increasing needs and the demands on my time and energy and emotions. I had a lot of unhappiness and upset and resentment--she was never there for me, she didn't take good care of me, so why should I have to do this?
I will be honest and say a lot of those issues for me, are probably still unresolved. I spent a lot of time with a therapist trying to work through things and it helped. What worked for me was to think about it from the standpoint of, what do I have to do, to be able to live with myself? What do I need to do, so that at the end of the day, I can look myself in the mirror and be okay with what I've done? That's mostly how I approach things.
My mother is now in a care home near where I live, and I don't visit as often as I might, or stay for long visits (she can mostly no longer manage longer visits so that's probably a moot point), or do a lot of the things that I know "other people" with relatives in a care home do with/for their PWD. Our lack of a past relationship means some of those things aren't practical or desirable. But I do care about her, and I do want her to get good care, and I do what I think, needs to be done. I make sure she is safe, getting the care she needs, and I manage all her finances and paperwork and so on, to the best of my ability. It's all I can do. (Some days I am able to be more detached and get on with things; other days the paperwork reduces me to tears. Nothing about dementia is easy.)
At the end of the day I answer only to my own conscience, and if possible, perhaps you can find a way to look at the situation like that.
You are important. Your relationships with your husband and daughter are important, and they are important. You have a right to your own life and those other relationships. Dementia will absorb all the time and energy we throw it, and then ask for more. Don't give it everything!
Sorry for all the rambling, but hope something in there is helpful. We are here to support you. Sending all possible best wishes.