He asked his ex to explain me that they are not together, she posted old photos with him to make me jealous but then made her profile private, why?

[Deimy]

[AviatorTom]

She may be jealous that he has moved on and found you, while she is probably still looking. So, she tried to get you to break up with him, then realized that wasn't going to work, so did a quick exit (private profile).

[CupcakeTheDestroyer]

Sounds like she wanted to fuck around, and then felt guilty about it because she knew she was in the wrong. Regretting toxic behavior happens from time to time.