I believe that she worked part time at a doctors office. As for her husband- every couple has a different marriage and different views about fidelity.
Yes. This.
I don't see anything wrong with harmless flirting. My friends all do it with each other and nothing bad happens. In fact, my hetero guy friends flirt with each other. (And no, they're not secretly gay, they're really hetero.) What is considered too much flirting and even what defines infidelity can vary by age, by culture and from couple to couple.