"Another year has passed. What on earth is that Vegeta doing? Is there anything more important than a caring, perfect wife like me?"
A while back, when Bulma hadn't heard from Vegeta for a long time and assumed something had happened to him, she went looking for the Dragon Balls. After making a wish to Shenron, she learned that Vegeta was staying on a distant planet to train for a whole year.
When Bulma asked Shenron to bring Vegeta back, Vegeta had ruthlessly refused.
Chapter 16