What she's experiencing is coercive control. It's probably been happening very gradually over the time she's been with him. I really feel for her. People are already saying there's no smoke without fire. As someone who has very recent of experience of someone threatening to tell lies about them, it doesn't matter if it's not true. It's not that simple. It's embarrassing, unprofessional, you worry about the what ifs etc. It's a horrible thing to experience even if you have the evidence to prove it isn't true.