Katie Blackmer, of Christiana, Tennessee, has the ultimate blended family. The 32-year-old lives with her husband, Ben Blackmer, 41, along with her ex-husband, 32-year-old Stephen Shepard, and Shepard’s girlfriend, Brandy Henderson, 31. The group is taking co-parenting to a whole new level, raising their six children together in a 2,500-square-foot home. And Katie says the parents wouldn’t have it any other way. “We call ourselves the ‘Blended 10!’ ” Katie tells PEOPLE.