I sympathize; my mother has been suffering from severe dementia for years and is now being cared for in a private facility. For a long time, my poor brother chose to try to keep her in his home, but it got incredibly stressful and even somewhat dangerous, as she got mildly violent. Since he's the father of two boys, it was an untenable situation.

If this helps, I wanted to mention that your MIL may not even recall her outbursts against you and your husband. Whatever resentments she has at the time, they're probably fleeting--until they surface again. That's the way it's been with my mother.

Unfortunately, the more we did for her, the more resentment she seemed to have. Hers has been rather a different case, because she has never been a good-natured person anyway--and her doctors said that this has some bearing on her behavior now and has, undoubtedly, made her act even worse.

In your MIL's case, though, it sounds like she probably forgets about her resentments, or only nurses them sporadically; and they're certainly unfounded, as you well know. I know it's hard, but you simply can't feel guilty or feel that you haven't done enough; you're doing everything that is humanly possible, and you've treated her wonderfully!