I found that sending a couple on vacation together seems to bump their relationship status up one rank. I was able to send a newly formed couple on 2-3 vacations and they went from "Totally in love" which seems to be the starting rank to "Let's get married!" That was early this morning and they still haven't married though. Meanwhile another couple formed and got married within about 10 minutes this morning.
I also got my first baby today. Lois Griffin and one of my irl friends. She has Lois' eyes and his mouth.
EDIT: Arya. is. pissed.
This is the first time I've seen someone get this mad.