I don't see it as an ethical issue whether a woman keeps her married name after divorce or reverts to her maiden name. Even if she does it out of spite.

I married young and didn't feel ready to give up that aspect of my identity, my name--it is how I thought of myself. Mrs <first-husband's-last-name> was his mother, not me! But I eventually started using ex's last name--without changing it anywhere legally--for medical/kids' school records as records were getting lost or confused, and I wasn't being properly recognized as my children's mother. This was back in the 70s/early 80s when a suburban, non-professional woman keeping her maiden name was an oddity.

The second time around, I might've changed my name what with 3 last names in the household, but second hubby's last name is very rare even in the Netherlands whence it came, hard to spell, hard to pronounce. My original last name seems less important as part of my identity, especially since my father died. But just yesterday, when we took a tour of the new local Boeing facotry under the auspices of a scientific organization of which my husband is a member...although he provided my real name, they used <myfirstname> <hubby's last name> on my badge. I didn't mind. My mother has always addressed mail to me using my husband's last name, which is more annoying.

I used my maiden name as my daughter's middle name and deeply regret it. She travels regularly to Muslim countries and it's a Jewish name. I've pleaded with her to change it, to no avail :-( She is certain nobody notices or cares. I am not so certain. A rose by any other name...