I am not in the same situation, but have a mother and MIL in the nursing home right now. My mother went in on her own even though I begged her not to, and my MIL has dementia so we were unable to have her live with us or have her stay in her own home anymore. It's not easy as our parents get older and we as children have to step in. I feel for you and hope you are able to come to a decision without to much heart ache or frustration.
It's hard to know exactly what the right thing to do is, and it definitely changes your life.