Well I am familiar with a software called Eblaster for the pc which you could install on a computer. I remember at the time you could find no trace of it anywhere (not easily anyway). It had a secret multi hot key to get to the settings. It would record at messages, keystrokes, websites, email, chat, what applications you used, you name it. Then it sends reports to an email address. I put this on my computer years ago. It cost like $100 or something.
I did noticed that the same company has an android version of it. That's what it sounds like to me. All it takes is a couple of minutes alone with your phone to install it. You would never find it installed. A hard reset should take care of something like this though. Also change every password on everything. If it has a keystroke logger then she may have recorded you typing in all your passwords to various places.
Link to the software
SpectorSoft - eBlaster | mobile for Android
Dang, that software is nuts.