Ubuntu - Other people can hear whatever I play during call

During Google Meet call, other people can hear whatever I can from my computer without me sharing my screen. It can be Youtube, FB video from Chrome or song I play on the Spotify app, whatever kind of sound I play. How can I fix this, I'm using Ubuntu 20.04.

For more details, I'm using a headset with only 1 input jack for both sound and mic. I connect this headset through a cable looks like below. It has 2 jacks on 1 side which connect to my PC for sound and mic. The other side would connect to the input jack of the headset.