"I think they feel my place should be being their mother and honestly I guess that's how I feel too? "
It doesn´t look like something you´ve been assured of... Besides, chances are they would volunteer you to be a grandma instead of their mother and, willing or not, you are their mother.
According to what I have asked to elders I know personally, they still like the idea of being loved to love, admiting a tendency to what it seems to be asexuality, I guess.
In my particular case, I never liked women my age and now, being older, I´m sure I like them the less... Maybe that´s why I understand "cougars" the better.
http://www.dnaindia.com/entertainment/report-jennifer-lopez-demi-moore-cougars-or-just-women-in-love-1841019