When HE doesn't want kids, EVER?

I've been with my boyfriend now for 6 years and we've had the chat about children several times. He has a very negative outlook on the future and says that he never wants to have kids, can never see himself as a dad or see children in is future, ever. 
As a young girl all I ever wanted was to be a mum, but I must admit as I'm getting older it is something that is falling behind in my priories in life.
We're only 21 so we still have a while to decide and have children. But I have always kind of in the back of my head thought oh he'll change his mind but even with the topic of grandchildren came bought up from his mum he told her not to be expecting any from him, which she of course tried convincing him to change his mind but he was set on the big NO.
He has said to me before that he doesn't want to hold me back from having children, and I should consider leaving him because he doesn't want me to miss out on being a mum...
Anyway have any of you girls had this issue and what was the result?
There is no way in hell I would ever trick him in having kids or deliberately "accidentally" fall pregnant, as I would want it to be an exciting moment not deceitful. 
Also, would you end a relationship because of the idea of never having kids? 
I am a little terrified that I will stay with him for another 10 years and get Into my 30s and be wanting children and it ruin our relationship that far in.