. Locally you should protect your computer/s with Software Firewall.
Some information concerning both of you is stored in the Router's log.
If the Route's is your you can protect logging to the Router with strong password.
If the Router belong to both of you make a split password.
I.e. like in the movies, you type half of the characters and he types the other half.
So the two of you need to be around in order to access the Router.