@Holidayshopping
Was waiting for this question
Sansa married Tyrion on the orders of Tywin and Cersei at the now exploded Sept under the eyes of The Seven aka The New Gods
This marriage was a legal one in state terms
Sansa married Ramsey on the orders of Roose and Littlefinger under a Weirwood Tree, in the sight of The Old Gods
This was in part because the Northerners pray to the Old Gods and rejected her marriage to Tyrion as
- Wrong Gods
- Coercion
- Unconsummated
- They were in open rebellion to the state at that time
Though she was technically a bigamist at this stage each side rejected the other marriage.
However her marriage to Ramsey was also coerced and in terms of Sandra's consent just as invalid.
What makes her marriage to Tyrion which officially stands in state terms interesting is that they never consummated it.
And this fact is what may end up making Tyrion and Sansa an alliance against Dany and Jon.
He is the ONLY man other than her father to treat her with the proper kindness and respect. And someone she will naturally turn to for advice. She rather liked him by the time they ran away.
Tyrion has referred to her as his wife to more than one character and Jon as his brother in law, so Tyrion considers her his wife, yes.