S.H.
Your son, seems to be a sensitive being.
Meaning, to routines and stimuli. Even if that is him having an ear ache. That is still, stimuli. An icky feeling one.
And you, are the one thing that comforts him and is constant to him.
So, don't know, what will get him out of that.
My firstborn, was very sensory sensitive. To any sounds or smells etc. And she also had a sensitive tummy per gas.
Anyway, even a toilet flushing down the hall, would wake her screaming.
For example.
I also co-slept with her when she was younger. Then from about 3-4 years old, she just naturally slept better. And was less sensitive to noises etc.
Also, though I'd co-sleep with her at times, it was not all night. We also had a floor futon in our room. And THAT is where, she could, if needed, sleep. For any reason or if/when she was sick. We explained this to her. And this worked, for us. She got sleep, and we got sleep. She didn't wake us when she came in our room to go on the floor futon. She just went there and fell asleep.
It was a good sleep compromise for her, and us.
By then, I had my 2nd child. Who was a baby at that time.
*And NO... my daughter did NOT climb up into our bed, from the floor futon. She stayed there. With no battles. She was in, our room. And that was good for her. The floor futon was not next to our bed on the side. But on the other side of the room.
Your son is of a certain personality. Your 2nd baby is of another personality. Hence different sleeping abilities and habits and needs.
I know it is hard, but try the floor mattress thing.
It worked for us.
And stop blaming yourself.
And tell your Husband, to stop blaming you.
What is, is. Your son is his own person. And each child, is different. If all kids/babies were the same.... then no parent would have any difficulties or conundrums.
You also, need to talk with your son. In ways he will understand.
He finds you, comforting. Sure, you are his Mom. You are always there for him. Nothing wrong with that. But, perhaps, try encouraging him to be a "Team" with you. Meaning... telling him things like "Help Mommy... to sleep. You are a big boy, I help you but you also need to help Mommy. Mommy gets tired. I need sleep to take care of everyone. You can sleep on the mattress on the floor. That is your place now. And Mommy is nearby. In the same room. Try for Mommy, okay?"
And hopefully, he also has a Lovey????
If not, get him one, that he chooses.
My son, loved to sleep with a stuffed animal... and he would rub that, all night. To comfort himself.
And, tell your Husband, if he is a snorer at night... that HE may even be waking up your son at night. By his snoring.
Because, it is the parent's sleep noises too, that can wake a baby or child at night.
If your Husband is so "negative" to your son or about your son because of his sleep habits... if I were a kid, I wouldn't want to go to sleep with him, either.
Also, your son is 29 months. 2 years old, is commonly, a very hard time per age, per sleep. It is developmental and per all the changes they are going through.
Remember that, their cognition is also changing AND their imaginations. So, it is a lot to adapt to, for a 2 year old.
But I have found, that from about 3 years old, a child naturally.... hits a different stage, per sleep. And they become better at it with less wakings.
So remember that.
Your child, is not so, odd.
And, from 2 years old, a child also starts to have, nightmares and general "fears" of things or the dark or anything. Again, it is all developmental based. And you can't just turn it off like a light switch. Their brains/cognition and imaginations, are changing. And their emotions, are not even fully developed yet, nor their self control.