Is a nursing home the right decision?

My mother-in-law has required increasing help over the fourteen years since my father-in-law died. With some hired help, my husband, his siblings and their spouses, and I have managed to keep Mama in her own home. She is 91 now and has nothing wrong that is likely to kill her any time soon. She does have painful debilitating problems, and her dementia is very bad now. She can't do any of the things she used to enjoy. She does nothing but complain. She asks the same questions over and over and over all day long. Even with this, we were managing pretty well until her children and their spouses began having health problems. I had pancreatic cancer several years ago and am still on oral chemo because I'm not out of the woods yet. Reactions to chemo have put me in the hospital several times in the past year, and my husband was in the hospital once for several days with spasms of the hiatal hernia and acute gastritis. He has other problems too. Still, our caregiving duties go on, no matter how bad we feel. Now my husband's siblings are soon going to be dropping out as caregivers for very good reasons--serious, crippling health problems in two cases and serious family problems combined with health issues in the other. Soon it will be just my husband and me, and there is no more money to hire additional help. Finally, my husband and I want to do a little travel before health and age make it impossible. I am 74 now--how many more years do I have to enjoy travel? We can't wait until Mama is gone. Her doctors say she is likely to live to 100. The only solution we can see is a nursing home, but we know Mama would hate it. In fact, she has said she'll kill herself if we ever put her in a nursing home. More important, we want to feel good about ourselves and how we handled this. I want my husband to feel right about how he treated his mother. What do we do?

A Daughter-in-law at the end of her rope