Dan and Shauna met their freshman year at Ripon College. At this time, they were good friends, going so far as to refer to each other as "BFF." After the two graduated, Shauna moved down South for graduate school and Dan moved back to Milwaukee. They remained friends but fell out of touch during this time. When Shauna moved to Milwaukee after her time in Mississippi, she contacted Dan to hang out. Dan and Shauna ended up coaching a club swim team together and spending many weeknights eating sweet potato fries and drinking beer at local establishments. After spending the majority of their free time together, the two realized that they had started dating. After Penny approved their relationship, the rest was history.
You'll have to ask Dan for his recollection of the proposal. Let's just say it had to do with dreams, walking the dogs, Lake Michigan, Kate hiding in a bush, and toy dinosaurs. Spoiler alert: Shauna said yes.