"I needed some alone time," Montag, 23, tells PEOPLE exclusively, confirming reports that she has moved out of the Pacific Palisades, Calif., home she shared with Pratt. "There are so many lies out there about me and I just needed space – even away from my husband."
But the reality star says there was no single straw that broke the camel's back and caused her to leave.
"I had to get away from the lies my family and supposed friends are saying about me," says Montag. "It's time to concentrate on myself."
Montag plans to spend the summer clearing her head and getting in some much need girl time with pal and new roommate Jen Bunney, which will be captured on film as they will be shooting their own reality show. Montag is also working on writing a movie script.
As for the future of Speidi, it's a work in progress. "I've always loved Spencer," says Montag, "but right now we're working on things."