ET caught up with the 23-year-old singer on Friday at Billboard's 10th Annual Women in Music event in New York City, where she denied rumors that the two are "secretly married," but did leave the door open for a possible engagement in 2016.
According to Demi, it's all up to her longtime beau.
"You gotta ask him!" she told ET when asked if next year could be a potential engagement year for the couple. "I have no idea."
The "Confident" singer has made it clear before that she will say yes if the 35-year-old former That '70s Show star pops the big question.
"I am very, very in love with him," she told a New Zealand radio station in July. "I think -- we will probably wait a little bit longer, but -- if he asked me tomorrow I would say yes."
"People were definitely judgmental," Demi added about the reaction when they first started dating five years ago. "Even my parents were like, 'I don't know, why is someone his age wanting to date someone so young?' It was after a while everyone around us started to see that what we had was real and incredible and very special."
Although it wasn't just Demi feeling the heat. Demi said people questioned the actor as well about why he would want to date her, given her highly publicized struggle with addiction issues. The former Disney star entered rehab in 2010.
"We started dating when I turned 18 ... Right after that, I went to rehab," Demi told Cosmopolitan in August. "People told him, 'You should probably leave. She's on a spiral, and you're going to be sucked down with it.' But he was like, 'I'm not leaving. This is somebody I really care about.' We relate on a lot of levels."
These days, the two appear more in love than ever. "I love you," Wilmer gushed on Instagram about Demi in November, calling her "honey." "Long night that was… But short when with you."
Obviously, the feeling is mutual. In March, Demi said she "wouldn't be alive today" if it wasn't for Wilmer. "My love has grown to a level that words could never possibly express how much this man completes me," she Instagrammed alongside a pic of the two kissing. " ... After sharing my ups, putting up with my downs and supporting my recovery... he still never takes credit and I want the world to know how incredible his soul is. I really wouldn't be alive today without him. I love you Wilmer."