During the process of moving house and settling him into a bed, we've got into a bad habit of staying with DS (2.5) until he goes to sleep. Then when he wakes up in the night he comes into our room to get me so that I can come and sleep next to his bed. It's the path of least resistance as he goes straight back to sleep and I can get some kip on the cushions on the floor, or nip back to bed once he's asleep. But now he's coming in twice a night to get me and I realise we've created an expectation and need to break it. I guess we'll do the putting him back into bed and then leaving thing repeatedly , but he'll be outranged at the apparently arbitrary rule change, and I do have some sympathy with that. Is there anything I can do to make this process easier?
I would just tell him that now he's settled into the new house, he'll be going to sleep on his own and you'll be going to sleep in your bed. Tell him how impressed you are that he's so grown up he's settled. At least then you'll have explained it to him so it won't be a surprise. Or, edge him in, stay with him when he goes to sleep at bedtime, then put him back to bed and leave when he gets up in the middle of the night.
After that, I think it's just sticking to your guns I'm afraid.