The singer split from husband Mike Comrie in January, and she says the change hasn't been easy.
"I'm separated from my husband right now, which has been a very difficult thing to go through, but we have a lot of love for each other and we have this beautiful baby," Duff, 26, tells Billboard.
She has been working on new music and admits there's a song on her upcoming album "about my separation and my love for this person, that maybe we're not meant to be together, or maybe we are. It's very, very personal."
Duff's album is her first in seven years, and she does some daring things with it – she sports a bikini in her new video, "Chasing the Sun," and collaborates with Ed Sheeran, the latter of which made her nervous, she admits.
"It was amazing to have him there and to have him be so involved. And it scared the s––– out of me too."
The former Disney star said that music began to call to her again when she was pregnant with son Luca, 2.
"I was about to give birth, I was actually pregnant, and I had, like, two months to go – I was a house walking around – and I just started writing a lot out of nowhere. I don't know if it was because I was hormonal and emotional, but I started writing and I took it as a sign that I'm missing that part of my life."