Finn, Poe and Rey are together in whatever arrangement you prefer (all three sexual or some pairs romantic or platonic) and Rey is pregnant with Finn's kid.

She insists on going on missions but when one goes wrong she ends up trapped with Poe - maybe in a crashed ship in a snowstorm, maybe undercover on a pirate ship or captured by the First Order.

Cue going into labour early with Poe doing everything he can to help while Finn fights to find and/or rescue them both...