We have a rule in my household, and I established it when we were dating. Took it from Everybody loves Raymond. The AIS rule. (Ass In Seat). If her ass is not in the seat at the time I communicated we are leaving, I leave. I did it a few times and she of course got mad, but it nipped it in the bud while we were dating and now we are 15 minutes early to everything. I am from the school if you are not 15 minutes early, then you are late.
Now we have a kid, and sometimes we are a little late due to her, but once she gets old enough to understand, I will AIS her ass as well.