It's hard to look at another's relationship, especially a marriage and understand what's going on and why. I got a little clue after my mother-in-law died (I never knew her, she died suddenly when we had just started dating but she knew about me) from conversations I had with my father-in-law about the marriage.

It does not sound like your mother sees it the same way you do. One thing I'd offer too, it's very hard to move from your home you're "use to" when you're older, no matter what. I'm only 56 and my husband, 63 but we recently moved from our home of 20 years and I found that hard! I can't imagine if I were older. I watched my parents/stepmother not give up their house until "forced to" and then they were bitter about it and unhappy, etc. It's hard to know how to help older parents.