I have an online product that sends motivational videos to users once a week for 20 or so weeks.
The users receive an email with a link to my webpage (Joomla). The webpage requires authentication (I have given the user a username and password already by now).
Once the user logs on, they see the webpage with an embedded Youtube video.

Now the question, I want to protect the videos without the users having to create Youtube accounts (so I cannot use the 'private' feature).
Only users, with authentication to my webpage must be able to see the embedded videos. Users must not be allowed to share the youtube link with others because then my onlie product will be lost to the big blue yonder.

Previously, I had uploaded the videos directly to my site but as more videos were uploaded and more users accessed, the website and videos slowed to a grinding halt.

Is there a way to link authentication from my site to youtube whereby a viewer is only able to view one of my videos by way of logging on to my site first?