[USB tethering] Find what app(s) drains my data plan?

Hello,

One app I use on Android relies on USB tethering to sync with its counterpart on Windows.

Problem is, if I forget to turn it off after syncing, some application(s) on Windows use that connection and drain my data plan

Is there a way to…
1. Find what application(s) is to blame
2. Prevent other applications beside this one to go through that USB connection instead of ADSL (soon: fiber)
?

Thank you.