Gustang is married to who? Is blossom same as yeon family head?

no, Yeon and Eurasia are different family. He used to married eurasia blossom but divorced now due to their daughter who's a princess of jahad got imprisoned by jahad himself for discovering the truth about the whole princess collecting 13 months situation. Yeon are the talented fire user meanwhile Eurasia family are those who are born with massive shinsu(mana) pool.

Thank you for this clarification. sometimes TOG is very confusing haha