EA link to Steam question (PC)

Currently my EA account is linked to my Fiancé's Steam account. I have bought content on his account for my games. We are wanting to unlink his steam and link my own steam so that we have our games separated. The content that i bought was bought through Steam not EA. My question is, is it possible to unlink his account and link mine? And if so, will the DLC I bought stay with my EA account? So far it's only 3 packs that were on sale and then 3 packs that were free sale items. I don't plan on buying any more content until we have answers.