But you will be banking on the fact that she will open the .exe file attachment, and that is a BIG IF.
There are other keylogger programs that can embed themselves in a .jpg, .doc or any other file, and you just have to hope the email service you or she uses doesn't detect it as a virus.
You get ONE SHOT at this, because if you tip her off, you are dead in the water.
My suggestion would be to try and setup a meeting, or have her come over to "exchange digital pictures". Like tell her you'd like BOTH of you to have all the digital pics that you both want, and make sure you have them all backed up.
Then you can run a silent install fairly easily that has been preconfigured.
Me - 32 Her -30 Married - 7 Years Together - 9 Years No Kids 05/21 - Bomb 6/8 - Exposed 7/9 - Re-Exposed 06/11 - She Filed