iPhone/iMac synch messed up

Hi all. My hubby and I both have iPhone 4s which we both sync to same iMac desktop. He accidently hot sync'd to my desktop. Now all my iPhone updates Always request his password (shows his login username).

How do I correct this? Thanks

Can you not restore your phone from a back up that you did before the accidental hot sync?

I don't kno. I'll have to look into that. If I do, it may b under older iOS version.
1. Husband accidentally synch'd to my acct. (i didn't kno)
2. I synch'd under older iOS version
3. Upgraded iPhone to iOS 5
4. Discovered husband acct shows up for apps updates on my iPhone.

I've been searching but no luck.