As devastated as she was, she never should have gotten a divorce. Everyone is going to make mistakes.
Bringing a prostitute into the marital bed was not a 'mistake'. It was a betrayal.
This. I'd see a divorce as the only reasonable step. (And to be clear: if my husband came home and was like 'X person... I'd really like to', or even 'hun, I messseeeeeed uppppp last night...', it wouldn't necessarily be a relationship-ending betrayal - like, the problem is the trust and lying and betrayal of trust, not specifically where he puts his dick. But 'oh hey, I found out that you've been deliberately lying and cheating on me to the point of bringing prostitutes into MY BED' is just the extreme. How are you supposed to trust anything about them, ever?)
HOWEVER, once the divorce occurs and you're free of the betraying untrustworthy asshat (and have paid for a fairly in-depth STD panel...), the NEXT reasonable step is to evaluate your finances and make your life suit your resources, and figure out how to fit the things that make you happpy in your list of priorities. (I have a hard time believing that Starbucks every morning is they key to happiness, but if Starbucks coffee, drunk at the table with a friend, once a week, is facilitating your social life? That's a 5$ rent for table space and friend-time, and ok, most people can make that work.)
The problem isn't the divorce, it's the everything after.