Jon Gosselin’s ex-girlfriend Hailey Glassman was deposed on Monday by TLC attorneys and found out that her boyfriend cheated on her.

RadarOnline.com talked to Hailey after the deposition and Glassman had some harsh words for Jon Gosselin:

He became a monster. He’s master manipulator and a compulsive liar.

I hate to point out the obvious, but didn’t Hailey worry that a father of 8 children who cheats on his wife MIGHT NOT be a candidate for most reliable boyfriend?

On Monday, Glassman got proof that Jon cheated on her — with former Star reporter Kate Major. She was the third witness deposed by TLC in their breach of contract lawsuit against Jon Gosselin.

Go to RadarOnline.com and watch the Hailey Glassman video clip.