Was there any character development?

I think the characters were interesting, but they don't really develop. The main character suddenly has an orgasm at the end...but why? What changed in her to be able to do that? Was it that she needed to be with strangers and not her husband? Nothing is explained.

Why does the creepy stalker dude fuck James right after rescuing him from a suicide attempt? Why is James happy now? So all he needed was to let someone fuck him? Seems like really shallow character development to me.