I co-slept with mine, and this is about the age that it started to tail off, but I did it fairly naturally.
I started by saying that we couldn't all share, and that we'd do one child each weekend night (they were too big for 3 in the bed - about 12 and 9 year olds). And that in the week, they'd sleep in their own beds (they shared a room, which helped I think, as they could hear each other breathing)
Then over time, the eldest decided he preferred sleeping in his own bed on his own, then a year or two later, the youngest the same.
Now they'll only come into my bed if they are sick.
Or if we're on holiday and we're sharing a hotel room (which is actually quite handy - that they don't mind sharing a bed with me/each other)
I know with my youngest, the more I lay down the law, the harder he digs his heels in - I have to work carefully and slowly to get things changed unless I'm prepared to really battle (eg. I was firm on the no bed share on school nights) - but only her dad knows his daughter and what will work here.