Ds was 9 when I married dh.
But we had been together since ds was 3. Ds didn’t know dh existed until he was almost 6 and we slowly introduced them over the next two years, then lived together at weekends for another year. So six years in total before me and ds lived with dh.
It’s possible to take things very slowly and keep the child’s best interests at the centre of things, always.
And if he had even looked at ds the wrong way, he would have been out the door.
That poor little boy.