Why would she keep trying to sabotage my relationship?

Helloeriss01
I still care about this girl.
I met her almost 2 years ago at work. she got promoted somewhere else and left the job then got promoted again back to our store.
She was now in charge at work. She’s only one year older than me but at first I thought she was extremely sarcastic and took her job too seriously. She does have a fun/loose side but can take her job seriously.
One day I wasn’t talking to her because I was in a bad mood and she went out of her way to keep asking if I was ok and if something was wrong because I wasn’t talking.
Every single time I would text / call my boyfriend she would say something and then tell the other managers on me which made me so mad at her and she knew this. She never asked about him and got quiet when I brought him up. She asked about other coworkers relationships.
One day I called him when we were clocking out and leaving the store ( so I could pretty much do what I wanted ) and she irritably told me to hang up until we were fully out of the store. after I told him I loved him over the phone.
She knew I was upset and gave me a reusable bag from the job lol. We weren’t allowed to talk about it but on her last day at work, she wanted to take individual pics with everyone and grabbed me by the waist and hugged me. I was the only one she hugged. She also told me she cared about me twice.
Also she said she was “come over and sing me to sleep” when I told her to stop singing.
She told another manager ( who im close to ) that she thought I hated her.
After she left the job she kept visiting and I missed her. Apparently she wanted to work here again. A little after she went out and met a guy and now they’re dating.
When I finally saw her again, she happened to bring the guy in the store and didn’t introduce him to me ( she did for everyone else ) and she barely made eye contact with me.
It’s been some time and I think they’re still together. Why would she not like my relationship so much if she was trying to find one for herself?
Why would she keep trying to sabotage my relationship?
6 Opinion