Well, one possible plot could be that Goku is under some sort of mind - control during a fight and accidentally hurts Chichi. Maybe an enemy has found a way to manipulate Goku's actions, and in his trance - like state, he strikes out at Chichi without realizing it.
In a 'chichi and goku married' fanfiction, the plot could revolve around their family growing. They already have Gohan, and perhaps they decide to have more children. There could be cute family moments like Goku trying to understand modern parenting techniques that Chichi is into, and also some action when enemies target their family due to Goku's reputation.
One plot could be Goku and Chichi deciding to take a family vacation. They go to a new planet with strange powers. Goku wants to train there, while Chichi is more interested in exploring the local culture. It leads to some comical and heartwarming moments as they try to balance their different interests and keep their family together.
Perhaps they are at a party on Kami's Lookout. There's a beautiful sunset in the background. Chichi has been waiting for Goku to make a move for a long time. Then, Goku, feeling a newfound courage, leans in and gives her their first kiss. The kiss might be a bit clumsy as Goku is not very experienced in such things, but it's full of love.
One reason could be ChiChi's overbearing nature. She is often very strict about Goku's training and how he spends his time. In fanfiction, this could be exaggerated to the point where Goku finally gets fed up. For example, if she constantly nags him about not doing enough chores around the house instead of training, it might push Goku to his limit.
Well, it could be that Gine, upon meeting Chi - Chi, realizes how much Goku has grown and changed because of her. They could all have a meal together, and during that time, Chi - Chi could learn more about Goku's Saiyan heritage from Gine. And Gine might see in Chi - Chi the qualities that make her a great partner for Goku.
One possible plot could be that the baby has an incredibly high power level from birth. Goku and Chichi are overjoyed but also worried about how to train and protect the baby. Maybe the baby shows signs of a new form of Saiyan power that has never been seen before, and they have to seek advice from the other Z - fighters.
Well, in many fanfictions, their relationship often develops through shared experiences. For example, they might go through tough times together, like dealing with threats to their family or the Earth. These experiences bring them closer and make their kisses more meaningful, as they represent a deeper bond formed through adversity.
One challenge could be Goku's constant training. Since he's always eager to get stronger, he might not spend as much time with Chichi as she'd like. This could lead to some arguments in their married life.
One idea could be Black Goku, with his different personality, trying to understand Chichi's strong - willed nature. Maybe he initially clashes with her over protecting Gohan and Goten, but then gradually comes to respect her maternal instincts.
It could be a new, self - created villain. This villain might have been training in secret for years, specifically to defeat Goku. He could have studied all of Goku's moves and weaknesses and then launch a surprise attack that causes Goku to get hurt.