The wife and I game a lot, and we each have our own PS4. We recently found out the neat option of only one of us needing to have a PS+ account for both of us to basically use it.
If you're reading this and are unfamiliar with how to do this, basically what we did was we made her PS4 my primary one (I have the PS+ account), and she logs in with her profile like normal. My PS4 is set as her primary (I'm not sure if this is necessary or not) but I simply log into my profile as normal and still use my PS+ as normal.
My question here is, if I were to purchase the Destiny bundle with Taken King via digital copy on my profile, and also download the game onto her console, would we both be able to play it at the same time with just the one copy?