Symun Fossoway

Simon Fossoway is an unseen character in Game of Thrones. He is a member of the House Fossoway.

Season 6
Talla Tarly eagerly greets Sam as he arrives with Gilly and her baby, complaining about her arranged marriage to Simon Fossoway. Talla seems to not quite keep the appearance of her future husband, because he has yellow teeth.

In the books
In the A Song of Ice and Fire novels, Talla is not betrothed to anyone in the books, and no character named “Simon Fossoway” has been introduced in the novels yet.