We're talking about the same Kirk who falls for all kinds of women in all sorts of TOS episodes, yes?So I think fans can be forgiven for wondering why, if she's such a big deal to Kirk, we've never heard of her before.

From where art thou pulling that idea?But Antonia's not just another ex. The nature of the Nexus means this was the happiest Kirk had ever been, and thus Antonia is the woman who made him happiest.
GUINAN: It was like being inside joy. As if joy was something tangible... and you could wrap yourself in it like a blanket. And never in my entire life have I been as content.