It is possible, and you could reinfect her as well. I really don't know what a guy could do to get rid of that. I am sure its simple and your doc would know. Antibiotics can be the devil!!!
Yes, it's possible you could have a yeast infection going. Whether it's from your wife or the antibiotics I have no idea. Get yourself some acidopholus tablets from the pharmacy and see if that doesn't calm things down in a day or two. It's the active ingredient in yogurt that helps restore the natural flora in your intestines, which are out of whack due to the augmentin.
I've also found that taking acidopholus while on augmentin (or any other antibiotic) prevents the bowel problems. Check with your pharmacist first to make sure the acidopholus won't interefere with the antibiotic's workings though.