Account transfer

So I was sharing and Xbox with my boyfriend and we bought Diablo 3: reaper of souls. Then the necromancer pack

I bought my own xbox for black Friday and the eternal collection for Diablo 3. So my boyfriend could be at his house and play Diablo with me.

We tried and it said that the necromancer pack was installed but he still had to buy it. When he signed into my Xbox it was installed and didn't have to pay for it. Tried going into settings than account to look for a transfer option couldn't find one.

How do we fix this?

Hope I'm making sense