Boys never not want their Mum. I have 5 brothers with families of their own and my Mum is still an important part of their lives.
Don't forget that it will be you who takes him to kinder, primary & secondary school, Uni or driving him to work before he gets his license and it will be you he calls when he wants to talk things over.
Teach him from a young age what fun it is to go out for milkshake/coffee together and that can be something that continues for many years.
I love seeing guys out for coffee with just their Mums or Dads with daughters. Maybe I am just a softie