Problem is, there are so many large trucks here, I just dislike the smell of truck exhaust. Hence the circulation button is always on. I try to open windows when I can but that is not always possible. Again, the TL was like that, the MDX is now like this. My friends CRV, same thing. The old integra, same bloody thing! When I take the BMW out, NO foggy windows! So frustrating.
OMG, well, then, there's the whole problem. You just can't recirculate for extended periods of time, outside of summer. If there is a difference between your BMW and your Acura, it is probably that the BMW doesn't truly recirculate as much as the Acura.
Your respiration dumps moist air into the car. More passengers, more vapor. More wet clothes and boot snow (winter and rain) also means more vapor. If you fail to circulate new air into the car, that vapor will build up, and condense on your relatively cold windows.
Other answers here give some bad information. Anything regarding the A/C is bad info. There is NO NEED whatsoever to fire up the AC compressor to get dehumidified air in the winter. Your heater dehumidifies the air because it heats it up, which decreases the *relative* humidity of the air. That's why it feels so dry in heated homes in the winter, even when it's raining outside.
But, bottom line, if you're not clearing out the stale in-car air, you are effectively just breathing straight onto the cold window.