Demi Lovato is marking a relationship milestone with Max Ehrich! The 28-year-old singer took to her Instagram Story on Monday to celebrate her six-month anniversary with her 29-year-old fiancé.Alongside a video of Ehrich playing with puppies, Lovato gushed over her man.«Happy 6 months to my darling, the best father these pups could ever ask for… Thank you for making my life so much better @maxehrich.