How was Sansa even allowed to marry Ramsay? Who would acknowledge it? They say it's because Tyrion and Sansa never had sex but how would anyone know that's the truth especially considering Tyrion's reputation?
Even if that is to be believed, they would still need an annulment. Lysa told Sansa "They'll execute that dwarf and you'll be free to marry Robin. You'll be the Lady of the Vale." She strongly implied that Tyrion would need to die before Sansa can marry again. Lysa didn't say Sansa could marry Robin because she never had sex. She could have forced them to marry at any point regardless of Tyrion's status if that was the case. That makes the entire marriage invalid but that was conviently ignored so Sansa could marry Ramsay and be fridged so Theon could get his redemption and cement Ramsay's status as the ultimate villain which was not needed.
Even if that is to be believed, they would still need an annulment. Lysa told Sansa "They'll execute that dwarf and you'll be free to marry Robin. You'll be the Lady of the Vale." She strongly implied that Tyrion would need to die before Sansa can marry again. Lysa didn't say Sansa could marry Robin because she never had sex. She could have forced them to marry at any point regardless of Tyrion's status if that was the case. That makes the entire marriage invalid but that was conviently ignored so Sansa could marry Ramsay and be fridged so Theon could get his redemption and cement Ramsay's status as the ultimate villain which was not needed.