I agree with MC Swag, I assume it was well known that Ramsey married Sansa, therefore implying the Tyrion wedding was never consummated. Sure, the whole world doesn't know, but enough people knew about Ramsey's marriage to Sansa to agree that the Tyrion marriage thing was old news and never official.
Besides, LF clearly has intentions of marrying Sansa, so he's pretty confident she is available in the eyes of the noble families.
I actually think it would be really cool if Sansa and Tyrion ended up together. Sansa has had so many suitors who's only intentions are to run the world and cause mayhem. It would be nice to see her end up with a nice guy afterall. But from Tyrion's perspective, he'd probably rather be her uncle than her husband. He still thinks of her as a child and would still feel bad "consummating" the wedding.
Besides, LF clearly has intentions of marrying Sansa, so he's pretty confident she is available in the eyes of the noble families.
I actually think it would be really cool if Sansa and Tyrion ended up together. Sansa has had so many suitors who's only intentions are to run the world and cause mayhem. It would be nice to see her end up with a nice guy afterall. But from Tyrion's perspective, he'd probably rather be her uncle than her husband. He still thinks of her as a child and would still feel bad "consummating" the wedding.