Sure. You can find a lot of fan - created stories on various fanfiction platforms. These stories might explore things like how they train together, their family life, or how they deal with threats in the Dragon Ball universe. They are family - friendly and can be enjoyed by a wide range of fans.
The relationship could develop out of a need for companionship. Gohan, having lost many of his friends and family in battles, is in need of someone who can understand his pain. 18, being an android with her own complex past, also longs for someone to be close to. They meet and initially just offer each other a listening ear. As they talk more, they find that they can comfort each other in ways no one else can. This emotional connection then grows into a romantic relationship, and finally, they marry as they realize they don't want to be without each other.
One possibility could be that in the fanfic, Android 18 sees Gohan's kind heart and strength. She might start to develop feelings for him as she watches him protect the Earth. Their relationship could be an interesting mix of her android nature and his Saiyan - human hybrid nature.
Gohan is pretty darn strong in the manga. He has moments of extreme power, especially when he unlocks his hidden potential. However, his strength isn't always consistent and depends on various plot developments and training.