There's a reason why I'm hammering you on the drive.
1) You will be concentrating on the road so your full attention will not be on her. 2) You need to be face-to-face during any discussion so you can gauge her body language. 3) You need to be in a "safe" environment for any talk. One where you can get up and leave freely when you feel your emotions start to take over. 4) There should not be any external interruption possibilities -- your son and grandson in the car could lead to distractions and abrupt interference when focus is required.
There are other things, but I can't recall them at the moment.
