Watson

Just apply no contact, she sounds like part of her does still live you but she is convincing herself she doesn’t and doesn’t want to be with you. By contacting her constantly and in depth and getting jealous that all comes across needy and smothering to the space she needs to sort her own head out. Sounds like she had no idea what is going on in her head and you need to give her time ALONE to really start to miss you. As for the ex, she is only with him because she is subconsciously trying anything to distract herself from the pain. Just act cool and ride it out. She will be back the anger shows there is still so much emotion towards you
Hope this helped
W