It was her boyfriend all along... >_< You can actually spot it within the first 10 seconds, and again at around 1:59 Min, where the mask clearly flickers during motion, making the edit much easier to notice.
Looking closely at "Clip 01", the edge between the couch and the person's leg shows noticeable masking/compositing artifacts. When he moves, the outline produces slight edge distortion, and the couch beneath briefly warps. This type of artifact is typical of a subject being isolated with a mask rather than being part of the original, unedited scene.
Another giveaway is the layering. "Clip 01" appears to be composited over "Clip 02", and whenever the foreground subject moves, the background briefly exposes black edge pixels (matte/fringe artifacts) around the masked area. These transient artifacts are a common byproduct of imperfect compositing and are generally not seen in a genuine, continuous shot.