I'm guessing ml was under mind control first chapter but she didn't know that so it seemed like he betrayed her. Looks like her green eye friend is up to no good and finna try sabotage her in any type of way. She most possibly was the one in the first chapter control her man. Once under control his heart went dark so his love could no longer reach her so of course it will unstable her powers and she can no longer use it. So now she back in time scared to love him yet impossible for her to stop. But I see as the chapter keep come she go find out eventually why he truly so called betrayed her. That's what I think just saying.
I've got a change of heart for this manga after seeing that(▰˘◡˘▰)