How can I explain to my mother that I can't live with her?

You don't owe her that, no matter what, you just don't. You don't owe her because she had you, raised you, helped you. That's what parents do for children. You only owe her a level of respect, caring, and oversight of her future. Just keep that in mind, maintain your independence, hold your head high and know that YOU matter as much (or more) than her. If you keep reminding yourself of these things you will know what to say.

A lot of people here seems to be stuck with the fact that they "promised" their LO they would never put them in a "home". That is a promise that must be broken. In most cases, the LO says to their adult child, "Promise me you will never put me in a home", and what are you supposed to say? Sometimes it goes out of the blue and you are taken aback and don't think to say what you really mean, which is some version of "Sorry, there is no actual way you can live with me". Some people are happy to care for their LO, especially a parent. This is hard work, very hard, that comes at a time when many of us are either winding down our careers, finally retired or maybe helping out with grandchildren. Our elderly mostly did not care for their own elderly loved ones, they got sick and died. Maybe they lived together for a time but they did not live 8-10 years with dementia requiring constant care. I think it is okay to "rethink" this promise if it does not reflect what you really want to do.

Often our LOs don't understand the scope or impact of what they are asking. You can't take care of her as she is romanticizing in her mind. How long has she been in the facility? It took my MIL 3 years to completely adjust and start becoming social and happier, not just from antidepressants, but also understanding that her pouting and refusing to get out of bed wasn't going to move the needle with us. Her transformation as of late has been incredible. Stay firm in your position, but hopeful. Divert her with outings if possible, or taking her to the social offerings in her facility. Don't allow every visit with her to be about breaking her out. Parents have no clue what they are asking their children to sacrifice, including their mental and physical health, and all because THEY didn't make an effort to come to grips with it prior. This is everyone's responsibility. Wishing you peace with your mom!

You won't successfully be able to "explain" anything to someone with dementia.

Her brain is irretrievably broken and it doesn't recognize her own needs. In her disordered world, she is "no trouble at all" and you are simply being mean by not taking her in.

It's a bit like an infant telling you that she promises to sleep through the night.

You would be entitled to feelings of guilt if you'd done something wrong. You haven't. You are looking out for your health; unless you are around, mother won't have an advocate.

When your mother lays on the guilt trip, tell her that the doctor says she needs a team of carers, not one elderly lady, looking after her. Keep your visits short and cheerful. Bring her a sweet, take her outside, speak to other residents and introduce her. Try going less frequently; that may lead her to interact more with others.

Yes. She is correct. You don't. Explain to her that it is too difficult for you to live with her. Most of us have problems living with the partners we CHOOSE, with roommates. It isn't unusual. So you explain that you love her, but that you are not up to living with her, that living with her causes you stress and anxiety. That you are sorry, but that is the case. That you are not asking that she change and that you know that in fact no matter how she may WANT TO, she is who she is and you are who you are, and it isn't working for you to live together. That visits will work well, but living together doesn't.
She will guilt you. That's fine. She will threaten, and break down and cry. That's fine. Normal reactions all. Not all of life is pretty. Much of life is hard and worth not going gently. Much of life is heartbreaking and worth crying over. BUT IT IS LIFE. And it is fact. And it must be accepted, no matter the grief.
So now, tell her gently and finally. Tell her that you will not argue the issue. That you love her but cannot live with her. That you will be the best you can be for her.
As I just said to another man, Welcome to the Club of the Flawed and Human.

Patchie, your parents divorced when you were three. Each of them promised ‘till death do us part’ - formally, with a whole crowd of witnesses. They didn’t keep their promises because things changed. That is the same for you, and you don’t need to feel bad about it. None of us have a crystal ball to know how things will work out in the future. Look after your own heart.

patchie, so glad you added the extra info in a reply! Great input in the previous answers. I am and only, with a mother who also doesn’t really connect to others, and acts like I’m her human lifeline. I think I went into this phase with more distance in place than you have now, she’s always put too much emotional burden with me and ~15 years ago I went to counseling and started making the changes *I* needed vs. just managing myself around what she needed.
Please, if you don’t have one, find a counselor through your insurance. We’re never too old to relearn and redraw appropriate boundaries with our parents! You’re involved and supportive of her - as a separate human being, not as a sustaining force. I’m just so proud of you for getting her in the kind of place she needs to be.
Consider the value of getting a counselor/coach now, and do the work. You’re worth it, and she’ll react in new ways to your new language and actions. A book or a forum can get you X far but you’ll go even faster with human support.
I SO understand what you’ve been dealing with all these years. We are not a tool for someone else. You are not actually capable of fixing this for her, nor were you able to fix anything in all the past years. So both sides end up broken hearted. Get out of that dance. ((Hugs))

Please do not feel guilty for not living with your mother. Your peace of mind is very important. Just continue to be involved in her care from the out side looking in.

So here's the thing.

You ask how to explain to your mom, that she needs to be in a care center and not at your home, although in the past, you have taken very good care of her.

And when you sit down to write her a note to explain it, her negative outlook ("you dont want me anymore, you're throwing me away, you've put me here to die") are all that come to mind.

(I'm looking at this situation and thinking, gee, you're in a nice facility with good caring staff, three meals a day, activities, volunteers who visit, other folks to interact with and a loving, caring daughter to advocate for me).

That's sort of proof of why she can't live with you, isnt it?

Her depression and illogical framing of all of life's events are catching.

So, no, you shouldn't try to care for her at home. In part because it's not possible or healthy for you to try to do the work of 3 shifts of caregivers. And in part because SHE needs to be protected from the negative emotions that you drag up.

Have you asked the staff how she is when you're NOT there? Is she mopey and moody? Or is she pleasant?

If she's sad and negative all the time, I'd look into getting a geriatric psychiatrist on board for an assessment. It's possible that antidepressant medication will make a big difference in her ability to see the good in life a bit more.

You will save yourself a lot of frustration and pain if you don't try to explain this to your mother. Even if she does understand, she will not acknowledge the validity of your point-of-view and she probably will forget what you said anyway and you'll find yourself explaining over and over again.