(Screenshot taken from the
Let's Play Archive)
When Kevin returns to the party, the flirty woman is standing next to two men. One of them (the blonde in a red jacket) looks like the guy she starts hitting on after Kevin turns down her advances. The other one (the brown-haired man in a blue jacket) looks like the potential husband.
I think the implication is that the flirty woman really is married and was caught red-handed when she was trying to seduce another man. In this case, the flirty woman is extremely unlikely to be Vita because of the lack of any references to a husband, current or former (the situation does give the husband grounds for a divorce), in Cold Steel. It's still possible that she was meant to be Vita back in 2007, but Falcom ultimately decided that Vita would work better as a single woman as they developed the plot of the arc further.
The problem is, there are other male guests who use these sprites, and these characters don't get any lines in this scene, so it's impossible to tell if the blue jacket really is the husband. It's also possible that the flirty woman has stepped it up and is trying to pick up two men at once. I guess this would somewhat improve the chances of the flirty woman being Vita, but it would still leave the questions of who "the oaf of a man" was, and why Falcom had decided to include an NPC hinted to be Vita's husband if Vita hadn't been meant to have a husband.
I think it would be really cool if the flirty woman was Vita, but I'm not going to believe that unless I see a callback to this scene that clarifies apparent inconsistencies in a later game.