Actually, I know damn well Darcy never sat down and thought about marrying Lizzie. If he had, it would have been a week before he was rounding up Bingley, sitting him down, and looking him in the eye like he was about to propose high treason and going, "Jane. You still down bad for her?"
Coin toss whether Bingley would actually get to answer before Darcy turned around and flipped over a whiteboard like
and launched right into the most detailed migration pattern known to Regency England to keep the extraneous Bennets as contained as humanly possible by rotating them between various Bingley/Darcy estates. Like, we're talking about trading them off for minor holidays a decade out kind of detailed.
"If you and Jane take them for Lady Day ten years hence, Elizabeth and I will take them for Michaelmas. We'll all be together for Christmas and Midsummer, so we'll divide the responsibility individually on those days."
This would be followed by thirteen different spreadsheets projecting joint expenditures so Bingley knows what sort of financial commitment he'll be shouldering and how to minimize it, what proportion Darcy will take care of, what the estate plans are in case Darcy predeceases anybody, when they should probably roll out various stages to keep it from affecting their respective sisters' ability to maximize their own husband-hunting--whole nine yards.
Darcy does not know that he'll probably be murdered when the Bingley sisters find out why he asked for their social calendars. He'd be marginally fine with that at this point, because the fucking Napoleonic War campaigns were not as meticulously planned as his roadmap to getting the other three Bennets satisfactorily married, and Darcy feels about as able as if he'd spent the last year on Elba.
It takes Bingley a few minutes to realize why this is happening, then he's like
"You proposed to Elizabeth?! Congratulations!"
Darcy... knew there was something he was forgetting.
That man would have kicked the Collins's door open with four binders tucked under each arm, dumped them in a pile in front of Elizabeth, and loudly announced that if they get married tomorrow he can have her entire family except for Jane extraordinary renditioned to the Scottish moors by Sunday and then been like
"Why are you yelling at me?! I promise you, it will work! You'll never see anyone in your family except for Jane again, I swear it!" when she starts yelling at him.