I am trying to connect my old Apple Watch to my new iPhone. Everything is reset, Apple Watch is updated. It keeps trying to connect to my boyfriends iCloud and not mine even though my iCloud was the one on the watch. We tried turning his phone off.

i am trying to connect my old Apple Watch to my new iPhone. It was used with my old iPhone and my Apple ID. This is the same Apple ID for my new phone. I reset the Watch, updated it etc. it is trying to connect to my boyfriends Apple ID. We turned his Bluetooth off and his phone while doing this. I do not know how this is happening. I cannot connect my own iCloud to my watch to use it. If you have any ideas please help.