I would say it is normal, and it is not dangerous for your relationship!
I have done it myself, not because I don't love my wife, or because I wish to find my ex and be with her ... but because I am wondering where she is and what is she doing. Just curiosity.
We were together for 1 year, and now, after 16 years, I just wonder where have life taken her.
Relax!
I have searched for many of my best friends from childhood. Just curiosity!