If you post a pic of your fiancee, we should have enough info to help you out. JK. Did you try both sets of keys after she told you this? Did she ever get it started? Maybe your battery is getting weak or losing a charge through out the night.
Sorry guys, I was walking out of the office when I posted this.
1 - it eventually started.
2 - battery was charged, it was turning over, just not starting.
3 - it had gas
4 - I don't know how many times or how long she tried it for.
5 - 45 degrees outside
6 - I assume Battery/Starter are fine, when I got home last night it started right up (with my key) and started up fine this morning (with my key)
7 - Brunette
We recently learned that one of the three keys that came with our 2007Pathfinder would turn but not start. You need to take all three keys and go to the dealer and tell them to reprogram them all. We just happpened to grab the odd key out of the kitchen draw this time.