What’s going on between them or I am paranoid? Whats happening?

Before my partner and I started dating, and when we barely knew each other, there was a girl he followed on Instagram who went to the same high school as him. When I first met this girl, she acted strangely - she appeared to be recording the interaction or pretending to be on a phone call, even though my partner and I weren't dating at the time. Then he came to my job then day before she came.

Later, when I started a new job, the same girl appeared at that workplace as well. She was staring. That same day, my partner texted me after days with no contact.

What’s going on between them or I am paranoid? Whats happening?
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