spina bifida risks....TTC...scared

Rose 🎀
My partner has the most minor form of spina bifida. He looks completely normal.
You would never know just by looking at him but he has spina bifida occulta, which is a neural tube birth defect that occurs in the first trimester. 
He told me that his father had it too. My partner had a complication and was paralyzed for a few months and needed spine surgery. But he's lucky that he can live a normal life.
I know that taking prenatal vitamins before TTC can greatly decrease the risk of neural tube defects.
I read that if a partner has spina bifida that your baby has a 1 in 25 chance of developing the condition (4% risk) . I'm very worried. 
Does anyone have any experiences with this or something similar when TTC?