The couple has been together throughout the coronavirus lockdown and the 27-year-old "I Love Me" singer took to Instagram on Tuesday (June 24) to make sure "The Young and the Restless" knew exactly how she felt about him on his birthday.
"BAAAYYBEEE - I have so much fun with you and there's so many things I want to say right now but I want to be present and spend this bday with you so I'll be quick: Being with you makes life SO MUCH FUN," the singer wrote alongside a series of photos of the couple together.
"We literally act like hooligans on the daily and don't give a F**K if we're embarrassing ourselves if others are around!! I spend my days with you, bare faced and in a bathing suit."
Lovato went of to tell her man she feels "unconditionally loved and accepted" by him, adding: "I can't explain it or you... you're indescribable, you beautiful, man. Inside and out you are jaw-droppingly gorgeous."
"You're also such a positive lil beam of light in my life and I can't wait to make more birthday memories together... here's to the future baby. I love you @maxehrich."
Max responded to Demi's love note, writing: "I love you infinitely baby."