What can I do? What options are there other than a NH?

Just say no to her living with you. Just say no to being her caregiver. If she has the money she can hire in home care. If she doesn't have money she will have to go to nursing home. Don't let guilt make you do something you will regret like moving her into your home. Once she moves in getting her out will be very difficult.

Why is what she wants more important than what you want?

The simple answer is that NO you cannot accommodate her. She could have been the best mother in the world and it still might not be possible to take on her care.

The only other option is to arrange in-home care if she is able to afford that.

Tell your mother "no". Do not take her into your home. Once she is in your home she is a tenant there whether she pays rent or not, and it is HER HOME as much as yours, and you will not be able to get her out of your home at all ever until death. Why would you do that?
And I also suggest you do not become her POA. If Mom is a senior at risk report her to APS. Tell her that you will not be caring for her, becoming her guardian or her POA as you are not mentally, physically, emotionally or intellectually capable of doing that. They will promise you help and resources. You will not get any. Let them know your Mom may need guardianship (conservatorship) of the State to get her on medicaid and get her nursing home. After all of that, if you wish to visit and lighten her day, take her out to lunch or some such, do so.
You should not have to sacrifice your own life on the altar to a person who abused you. You have a right to your own life. Your Mother has had her life,and now it is time for you to have yours.

Perhaps Memory Care or she can hire a caregiver.

Whatever, just don't take her into your home. Once they move in, they are very difficult to get to move out.

Good Luck!

Memory Care Assisted Living is a good option for your mom if she has money to private pay. Does she have a house she can sell to finance her care? Or good enough income each month? If not, then she'd have to apply for Medicaid and go into long term care in a Skilled Nursing Facility.

Its sad that she's got dementia now and no plans for her care, but don't have her come live with you! That's always a mistake with a history like you two have. Nobody wants to live in Skilled Nursing, but it's what happens sometimes when old age and disease sets in. It's not your fault, so don't fall into the guilt trap you're being set up for.

Good luck!

If she has the money maybe Memory care. But she seems to need more care than a MC can give. NH is your option. If she has money, use it to get her in and make sure the facility takes Medicaid. About 3 months before the money runs out, file for Medicaid. Once in a NH you have pretty much have no responsibilities. All her needs are met. You do not need to supply anything. They put a small amt from her SS into a fund for her personal needs. Like having her hair done.

People seem to dread nursing homes. There are some wonderful ones with dedicated workers. Please remember that your LO belongs in a place where she can get the best care possible. Such places are not necessarily what we would want for ourselves when we’re healthy, but when we’re not healthy we have to adjust to different standards.

Saying no does not mean you're a horrible or merciless person -- as mentioned by lkdrymom, many adult children are unable to take care of their stellar parents. Your own family needs to be priority.

I would start by reporting her to APS tomorrow. If she is struggling to do her ADLs (activities for daily living) they might act soon to get her placed. There is no option for home care in her situation without you being the manager. There can be a lot to manage.

Eventually the county will assign a guardian/conservator. My SFIL had a qualified guardian from Luther Social Services and they were very good to work with. Your mom won't like it, so be prepared for this. The guardian will assume authority over any and all of her assets (including home) and her medical decisions. I wish you much peace in your heart as you go on this journey.