I am sooo glad there are other women having this problem!! I will say that you definitely don't have to be a larger woman to have this problem!
I am finally in the 50 mile mark and am suffering from agony as well!!
I think I measured by "sits bones" correctly and they are only 3 inches apart!
I originally had front saddle pain, then switched to a Sella saddle (with the center of the front cut out) which alleviated the front pain, but now I have severe pain on my sits!! Barely was able to ride 45 minutes!

Any suggestions?

Suzy