I have been thinking of this post for a while. And I think that this is where a lot of women have problems, myself included. Society is no longer set up to 'deal' with SAHP. It's incredibly isolating. Before, there would be other SAHP (mostly moms) in the neighborhood. People lived and worked much closer to home. Multi-generational living was more common, and even if not, Grandma/Granpa lived nearby. Some aspects of housework were communal. A community bakery, frequent shopping for fresh items, even laundry was usually done on the same/similar days. So, for example, while I would be hanging out laundry on the line, so would Francine. We might not have been the best of friends, and I'm sure there were people one didn't get along with, but the social isolation was not as severe as now.
Also, children are not as welcome in as many places. I don't think that's changed much, but being a sole caretaker, at times, I can't leave the house without the kids. And if I'm not welcome in many places, that restricts me a lot. Which increases the lonely feeling.
I love being with my kids. I love seeing them grow up. But I am more than 'just' a mother. I feel, sometimes, that because I am a SAHM, that people think that all I want to do/be is a mom. That my interests only revolve around being a mom. But I am a grown woman. I should have outside interests. I should also have time to myself, even if it means going to a playgroup so the kids can blow off steam while I use my brain with other moms & dads. :)