True, this is not good behavior from her, but the husband needs to find out why the wife is talking to another man.
She may not have some to him sooner maybe because she didn't think he was approchable or would understand what she wanted or needed, but you are right, her husband should be her first point of contact.
I talk to my fiancé a lot, and we send more than 2000 sms messages a month. Insane, I know, but we enjoy talking to each other and always being in contact. We just talk abot random things, whatever is going on at that point in time, or nothing at all. Its just nice to know what we are on each other's mind.
If I'm busy in a meeting or something, or have something to do, she does wait, because she does know I have things to do, but if she doesn't hear from me in a day, she gets worried.
I guess it comes back to communication being the key. I'm going to marry my best friend, the love of my life. I don't see a reason why I wouldn't want to talk to her as much as I can, let her know I'm thinking about her, and I know neither of us would ever want to talk to another person the way we talk to each other.