Your vet should be contacted immediately whenever there is a big change in behavior. Often this is one of the first signs that something is going on with your pup and it's very important to make sure there is nothing brewing. I hope you can get to the bottom of this quickly, as I would imagine your wife doesn't like being attacked!
__________________  Shannon & Puff 
"All his life he tried to be a good person. Many times, however, he failed; for after all he was only human. He wasn't a dog." Charles M. Schultz |