The actor - who raises Maddox, nine, Pax, seven, Zahara, six, and biological kids Shiloh, five, and twins Knox and Vivienne, two - with Angelina admitted the couple`s brood are putting pressure on them to tie the knot.
He told USA Weekend magazine: "The kids ask about marriage. It`s meaning more and more to them. So it`s something we`ve got to look at."
Brad, 47, started dating Angelina, 35, in 2005 shortly after he split from first wife Jennifer Aniston.
Angelina has been twice married, to actors Johnny Lee Miller and Billy Bob Thornton.
Despite their large family, Brad insists he and his `Tomb Raider` star partner get plenty of opportunity for intimate time, and don`t like to hide it from their children.
He added: "We tell the kids, `Mom and Dad are going off to kiss.` They go, `Eww, gross!` But we demand it."
The `Tree of Life` actor also tries to give his children as much of a normal upbringing as they possibly can, considering their parents are huge film stars.
He said: "Angie and I do everything we can to carve out some semblance of normalcy for them, to recreate the kinds of moments that were special for us.
"It`s not unusual for the kids to be covered in paint. We have mud fights. It`s chaos from morning until the lights go out.
"We`re hunted. Our kids have to live behind a gate. Outside, there are people with cameras. But I`ll take the trade-off."