Britney Spears' sister Jamie Lynn was heart-broken after she discovered that Casey Aldridge, the reported father of her unborn child, has cheated on her.
Aldridge is reportedly dating another woman known as Whitney Seals from Magnolia, Mississippi.
Seals' brother, Kevin confirmed that the two have been dating for months.
"Whitney and Casey have been dating for months," Contactmusic quoted Kevin, as telling MSNBC.com.
"I know Jamie Lynn was really upset and jealous when she found out about it," he added.
The 16-year-old had recently confirmed that she is pregnant with Aldridge's child.