why is my iphone 5 safari history found in another person's iphone 5?

Both my mom and I uses Iphone 5. I had let her login to my itunes in her phone to let her download stuff and I didnt log out of it but i don't use iCloud either. So today, my mom asked me to help her search some things on the internet and passed me her phone. i was surprised to see all my current history in her phone. I tried deleting the history but it was still there. the only way i managed to get rid of it was to delete the cache. It was really surprising as she had the phone for 3 months and I am afraid that she might have actually seen some personal history in my phone. She is an IT idiot, so i doubted that she had actually planted a bug onto my phone to spy on me. I believe it was something to do with the itunes account but could not verify anything. Has anybody encountered this before? I am not sure if logging out of itunes on my phone will break the connection, i do hope that somebody can help me fix this. thank you.