The 'Confident' singer split from the 37-year-old actor last year after six years together and though they remain friends, she admits things could turn romantic again one day.
Asked if they could ever get back together, she said: ''You never know what's going to happen. I don't know what's going to happen.''
But for now, the 35-year-old star - who briefly dated MMA fighter Guilherme 'Bomba' Vasconcelos after splitting from Wilmer - is happy to be focusing on knowing her own mind and appreciating who she really is.
Discussing whether she's found herself yet, she told 'Entertainment Tonight': ''Yeah, I think I found her, and I think I'm still finding her.
''And that's why I'm not diving into anything with anyone. I value my time by myself now, and I value my time with my friends. And I just have learned to really appreciate my me time and getting to know myself and learning to fall in love with myself before I fall in love with anyone else.''
In June, Demi admitted she and Wilmer are still ''best friends''.
She shared photos on her Instagram Stories and Snapchat feeds featuring herself and Wilmer sharing an embrace and looking delighted to be with one another.
She captioned her Instagram post: ''Best of friends no matter what.''
The actor has previously said he only wishes ''incredible things'' for his former girlfriend.
He said: ''Honestly, I only wish nothing but the most incredible things for her.''
After the 'Cool for the Summer' singer split from Wilmer, she later revealed she did so for the sake of her health, and to ''start fresh''.
She said previously: ''I think it's healthy to be able to start over with someone else. Being sick was always a part of my relationship with him; I always had something wrong with me. I needed to let go of that.
''It was hard to depart from somebody who saw everything, but it may be nice to start fresh with somebody. Because that person I was when I was a lot younger is not who I am today.''
All I Want For Christmas is widely regarded as one of the best festive tunes every year
Pearl Jam announced 14 dates in the UK and Europe in June and July 2018.