"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, told Billboard.
She also revealed that the couple's split inspired a song on her highly anticipated new album.
"[There's a song] 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," she shared.
Duff and Comrie, 33, announced their separation in January, but have been continuously spotted together, including at this year's Coachella.
They have one son together, two-year-old Luca.
"We're constantly seen together and people are like, 'What are they doing? Are they back together? Are they not?' We're really good friends and we have so much respect for each other and obviously Luca is our No. 1 priority," she told E! News in May.
"I think we got to a point where we were like, we really need to honor happiness and whatever that is and however we need to sort that out or work that out, we're doing that. We love each other so much and we love spending time together. So when you see us out it's not just for Luca, it's because we make plans and we hang out and we don't know what our future looks like right now but we're both doing really good and just figuring out what makes us happy."