fascninated "by" or "with" her married life?

I have found some useful resources for my question:

"Fascinated by" and "fascinated with" are very much interchangeable, but when saying that you are attracted to someone's charm, you would say "fascinated by (him or her)".

This is an excerpt from "Collins Cobuild English Usage".

Additionally to your own find I can offer the popularity results from google books. This ngram and this one show that fascinated by seems to be generally a lot more popular that fascinated with.

The in depth searches (by, with) show that you are already on the right track. While the difference for fascinating ideas is times two, it is a factor of five when referring to charms.