As many people know, Duff was married previously to Mike Comrie, and the two share a son, Luca (via Distractify). The timeline of their relationship moved pretty quickly — in 2010 they wed, in 2012 they welcomed their first and only child together, and by 2014 the couple had separated. In 2016, Duff was officially divorced from Comrie. Flash forward a few years, and Koma was proposing to the Lizze McGuire star in a park near their home. 

As Duff recounted toVogue, "All of a sudden he says, 'I've been working on something for you, and you're going to love it. I really want our kids to know our story and now we can keep adding to this book.'" She goes on to describe the sketchbook he gave her: "It's our whole entire story mapped out for us to refer back to as we get older and for our kids to know, which is amazing. I get to the very last page, and there's a little piece that I have to lift up and my ring was inside. It was so sweet. It was really special and really simple, which is very much how we are and how we operate. Then it started raining, and it was perfect."