Clearly, I understand the concept of privacy, but such behaviour is a clear indicator that your Indonesian girl is hiding something. If you believe that, then you can ask her about the previous men she was dating.
I remember my ex was very confuse about it: She was telling me about her Dutch guy with whom she had been for 3 years, her American guy she had dated for 2 and a half year, her German guy that she had loved for 4 years, etc.
My ex (which I found out was cheating) was behaving very strangely with her phone: First, the screen was locked with a password.
However, if you are looking for a serious partner, then do not tolerate a relationship based on mistrust and lies.
This is not an exhaustive list of all the signs that can exist showing your Indonesian girlfriend is cheating on you.
After 5 years leaving in Jakarta, I think I’ve heard 100 hundred of these stories.
It is very common for anyone familiar with Jakarta nightlife.