The couple started dating in 2006, shortly after Diane finalized her divorce from French film director Guillaume Canet. It appeared that they were in it for the long haul after the actress, who celebrated her 40th birthday in New York over the weekend, revealed that she had finally made the move to the United States to live with her longtime love.
And while the couple's union was the definition of #relationshipgoals for many years, their love story hit a roadblock last fall when rumours swirled that Diane had a fling with her Sky co-star Norman Reedus.
The A-listers never shied away from praising one another, with Diane even crediting Joshua for bringing perspective to her life. Speaking with Town and Country, the German actress said, "I had become arrogant. I had been a model, I spoke three languages, I had a career. I felt I had figured it all out ... Meeting someone like my partner, who has a very different perspective, who likes to travel in a different way and be open to various experience was so important."
Both stars always insisted that marriage wasn't important to them and that they didn't need a piece of paper to define the bond the shared. "I don't feel any more or less committed to Diane for not having stood in front of a priest and had a giant party," said the Vancouver native, adding, "We're both children of divorce, so it's hard for me to take marriage at face value as the thing that shows you've grown up and are committed to another person."