Yeah, Lulu was dating Chappu, Wakka's brother, prior to the events in X. He was killed after joining the Crusaders, and then during X, she seemed to get really mad at Wakka every time he compared Tidus to Chappu. Old wounds and whatnot. Definitely not a good way to start a romantic relationship, in my opinion. But they somehow ended up together in the space between X and X-2. I can't remember how long of a gap there was between the games, but they ended up having a kid right at the start of X-2, if I remember correctly.