It isn't in an episode it's in a movie: Super Android 13
Chat with our AI personalities
The episode in which Chi Chi and Goku fight is episode 137. It's also the episode in which Chi Chi becomes Goku's fiancee.
They dont. Goku accidentally proposes.
they get married on the last episode of dragon ball when goku has to save chi-chi's father from burning in the flaming castle episode 153
Dragon Ball 134 Preliminary Peril
They get married in episode 153 The End, The Beginning of Dragonball