I am single, so that's probably a bit different (no competition in the bed!). But my ex was all about co-sleeping so from DS's birth, my son never had his own room, and certainly I kept that up once we divorced. I slept with my single-mom until I was 10, but I had a bed in my room. I think about that now because my son does Not have a bed in his "play room" and this summer there have been some social moments where kids are over and asking where his bed is... "I sleep with my mommy" is still an OK answer, but I wonder if that will change... even if he still chooses to sleep with me, he might want a bed in his room so it Looks like he sleeps alone (I remember feeling that when I was young... and it gave me a place when I had sleep-overs).
My movement to my own bed at 10yo was very natural... I think one day I just wanted the space to myself. I crawled in her bed for a few more years in the morning or on nights with bad dreams.
My focus is on his Going to Sleep triggers - I do not go to bed with him. That is his time to be alone and if he's scared, he calls for me, just like an alone-sleeper would be. So really the co-sleeping just eases any night wakings, and certainly snuggle time in the morning.
single, WAH home, to my only very kind & sweet lil man