And the 18-year-old star has already moved on – she's reportedly dating businessman James Watson.
"She did a lot of growing up but he didn't," a source told the mag of Aldridge. "I think she put up with more than she cared to put up with. She just got enough of it and was tired of the situation."
Watson, on the other hand, is 28, 10 years older than Jamie Lynn. According to People, he would not comment on the relationship.
Jamie Lynn announced her pregnancy – at age 16 – in December 2007. Her baby, Maddie, was born in June 2008.
The former couple had planned to marry, but in March 2009, OK! reported that the engagement was off.
"The wedding's off," a source told the mag at the time. "They are still in love, living together and very happy, but they have no plans to get married. Jamie Lynn has everything she wants and feels no need for a ring and piece of paper."
Related Content from AccessHollywood.com:
VIEW THE PHOTOS: Jamie Lynn Spears
PLAY IT NOW: Access Archives: Jamie Lynn Spears (2002)
PLAY IT NOW: Access Archives: Jamie Lynn Spears (2004)