Constantly asking for password in iTunes

Question

Not exactly sure when it happened, I believe with the update to iTunes 11 - but am not sure, I am now being asked to enter my password every time I turn around to do much of anything in iTunes.  I'm asked sometimes as many as 3-4 times in a row (as if it were for different processes).  I know I'm not mistakenly entering the password (thought I was at first), as I've used the paste command to paste my password in every time it asks, so I know it's consistently entered.
I use Home Sharing, so iTunes is always running on my iMac.  Every time I want to check for new IOS apps (about every other day, sometimes every day), I am asked for my password.
Behavior prior to this (iTunes 10), was to ask when iTunes started, and then it remembered the password.  I've searched here, and tried many of the suggestions - and they don't work (deauthorizing the computer, reauthorizing it, etc.)
I understand security - but this is getting ridiculous.  This morning, I had to enter my password to start iTunes (I rebooted), plugged my wife's iPhone in, found there is the 6.1.2 update for her phone, had to enter my password again, searched for new IOS apps for iPad/iPhone/etc. and had to enter my password a third time.  All of this within the span of 4 minutes or so.  Security is one thing - this is downright annoying (and that's the "public" consumption phrase - not what I'd really like to say).

Answer 1

I'll just add - went to iTunes to "buy" a free app.  Within 15 minutes after going through the above rigarmarole, and it's still downloading my iPhone update, and the updated apps are still queued.  I was asked AGAIN for my iTunes password.  That's 4 times within 18 minutes or so. 
Since each time was a different "area" of code (startup, download iPhone update, download app updates, purchase new app), I'm suspecting that there's something broke in iTunes, or screwed up in my Keychain and it keeps asking for a password each time I go into that "section" of code.
However, I can guarandamtee that if I check for updates within 20 minutes or so - I'll be asked for my password yet again.  Just thought I'd check to see if it would now - I've got my download window open, won't open the main window at all.  I'm going to have to exit the app and start AGAIN to get my main window back up again.  But I won't do that until my downloads are complete.