co-sleeping with a 3 year old.. it's about that time..

I always said we dont co sleep with DD , but when she sleeps in our bed 5-6 nights a week, i think it may be the case.
DH works FIFO so when hes away, i actually enjoy sleeping with her.. but when hes home, somehow the 3 of us in a king size bed just DOESNT work.. shes getting too big to share the bed with all night, she goes side ways, he sleeps in the middle and i end up teetering on the edge.. or im in the middle coz DH wants to be close to me and i end up sandwiched between the 2..
I just need some advice on getting her sleep in her own bed, its not that she flat out refuses to sleep in there, its that mummy is lazy and we usually go to sleep in our bed together. Im thinking of starting a bed time routine.. because we dont have one of those :hides:
im happy to start with Baby steps, and work our way together comfortably in the right direction.