Entity Reference - adding fields to reference?

Question

I'm using taxonomy and nodes to create a tree structure. Inside the taxonomy term I created an Entity Reference (referencing to nodes). I know this looks like the world upside-down, but for this time this was the easiest way.

Term1 (reference to:) - Node A, Node B, Node C, Node D
Term2 (reference to:) - Node B, Node D, Node E

I want to add custom fields to the node, but with different values for each reference. Let's say I want to add a date field with different values for each reference. Adding a custom field to the content type won't work, because they will be the same for all references.

Answer 1

The Entity Reference module does not support this. You'll want to check out the Relation module. With this module the reference (relation) itself is a fieldable entity.

I do realize you'll have to write an update function to migrate your current references to relations, but aside from creating a custom table as @FriOne suggested, it's the only way to go as far as I know.