Skylar Grey says she desperately needs protection from her ex-husband ... a man she claims is secretly recording video of her in her home, and threatening her boyfriend.
In legal docs, Skylar says Todd Mandel hired private investigators to track her current bf, Elliott Taylor. She also says her ex has threatened to physically harm Elliott.
According to the docs, Mandel is also surreptitiously recording her in her home ... using hidden cameras and recording devices to monitor her every move and word. Skylar -- who's featured on Eminem's new album -- says she found out about this Wednesday night during a party ... when Mandel told her he was "stalking me and is following and monitoring me and my boyfriend."
In the docs, she says she learned Mandel has screenshots of private pics of her. The most menacing part came when Mandel allegedly told her "he planned to physically hurt her," and he was going to do it within the next 2 hours.
Although he, apparently, didn't attack her that night ... she believes he's violent and dangerous. She requested, and was granted, a restraining order requiring Mandel to have no contact and stay 100 yards away from her, Elliott and her roommate/assistant.