That's how I've understood it. Tiffany isn't visibly pregnant when we see her in 1999, so she hasn't been pregnant for long. So either she hadn't been with her ex for long (which isn't entirely consistent with the violence of his reaction* when she leaves him), or she cheated on him. And I'd prefer not to think the latter of her.it’s possible (though not certain) that Jessica’s dad is Tiffany’s ex
* Yes, he was obviously violent anyway. But presumably if they've only been together for a week, he's not going to care nearly as much about her leaving him as if they've been together for a year.