How do you find your facetime call history on iphone/ipad?
FaceTime history are stored into each device you make FaceTime calls with.
It looks like Apple don't let us see our detailed history, only a global one with recent calls. But there is something we can be 100% sure about : is that the complete logs are stored somewhere on your device.
In my case, even with Handoff and Continuity enabled, FaceTime calls made with one device won't show up on others after hang-up, expect when I make a classic phone call from my Mac using my iPhone.
The only way to find it, would be to extract your device's save file and browse it through a third-party-app.