People with high myopia is prone to retina detachment. But that does not mean it is inescapable. Myopia is hereditary, while RD is not. There might be some genetic factor, but you do not worry too much actually.
The signs of RD are night blindness, decreased vision, etc. Sometimes, like a black cloth covering in front of your eyes, and then the eyesight recover instantly.
Do not do strenuous exercise, like running, jumping, swimming, etc.
Till now, there is no reason shows that retinal detachment will inherit to children. In fact, the only way that your children would get high risk is if they have serious myopia or other eye disorders such as retinopathy of prematurity, diabetic retinopathy, Marfan's syndrome, congenital cataract, etc. If not, you don't worry that they will get retinal detachment.