He's in his mid-thirties which is on the older side for a football player. He's also one of the best players at his position in the league (although he may have lost a bit this year.)
But if he did go to a different team, she'd go and cheer him on at that team as most wives and girlfriends of players do.
A breakup could be interesting but it'd just mean she's not at games. She hasn't been at every game. She missed quite a few because of her touring schedule. Her being at the games has raised interest for people who may not have paid attention to the sport before but it's not like the NFL needs Taylor Swift. They're still popular. This is just an opportunity to expand that fan base.
