Xbox Live Gold sharing

Both myself and my son have xbox one consoles and both have separate xbox live gold subscriptions, separate gamertags etc etc. Do we need to continue to pay for 2 subscriptions in the same household or can we both share the same subscription but continue
to use separate accounts/gamertags if that makes sense?

We both play same games etc so like to keep these separate but didnt know if that meant having to keep using two gold subscriptions.

Thanks

:)