A friend of mine has a daughter who had trouble sleeping alone. She too is a single mom, and her daughter was struggling with separation anxiety from both parents at about the same age. Sometimes, she would let her daughter sleep on a little “pallet” on the floor in her room. She would have her bed to herself, and the daughter would sometimes wake up uncomfortable and decide to go to her own bed. Eventually, she did grow out of it.
Sleeping with a pet can help comfort children who have trouble sleeping on their own at night, too. Just having a friend there can make them feel more secure. Especially if it’s a bigger friend, like a dog. Anxiety is crippling, and it can make the most simple things, like being alone, feel impossible.
I’m not a doctor or anything, but here’s my opinion. I don’t think you should just submit to letting him sleep with you when you don’t want him to. You have a right to a good night’s sleep! But it also sounds like he believes he can’t sleep alone. The lies anxiety tells feel real to the people experiencing them, and kids often don’t understand what they’re feeling, let alone why. Sounds like y’all are both in distress. Have y’all tried counseling? Getting to the root of his anxiety and addressing that might help him face whatever fears are keeping him tied to your hip.