Ooooh, A., I feel your pain! Its SO stressful to go night after night without sleep, we went FOUR years like that. I too spent many nights sleeping on the floor, and if I DID get to my bed, she'd come get me two or three times per night. It was SO frustrating, I was mad at everyone, my back hurt, I was too tired to do anything about it.
I think you're right, its getting him to put himself to sleep that is the issue here. if you can get that resolved, the night awakenings will likely resolve too.
Here's what I did, its from "Raising Your Spirited Child" by Mary Sheedy Kurchinka (some of the best parenting advice I've ever read, whether your child is "Spirited" or not). It took a few weeks, but the method in there worked great, no crying! We sleep through the night, all in our own beds. Everyone is happier, especially me!
1. Its already been said that its important to have a set bedtime routine. Make sure its something you don't mind doing for YEARS. Keep the routine calm but pleasant for everyone.
2. Once your child is in his bed, keep him calm, no tickling, wrestling, etc. His bed is FOR SLEEPING. (e.g. be boring)
3. But go ahead and stay with him until he is sleepy. This is your time to talk, connect with him, share about your day, cuddle. you said you work alot, so he might be using the nighttime to connect with you. So don't scrimp on this time with him.
4. Here's where you make a change: He needs to practice being alone. So during this connect and cuddle time, You need to make up an excuse to leave the room for a few seconds. ("Mommy has to go potty", "Mommy needs to feed the cat real quick" "Mommy needs a kleenex", "Mommy needs to get your teddy bear") Tell him you will be right back. Leave. Come right back. The first time, just leave for few seconds or so. If he cries a tiny bit, that's OK, but you don't want a full blown cry - that's not sleep inducing!
Then gradually, over a period of weeks, increase the time you are gone. And one miraculous night (sooner than you'll expect) you will come back and he will have fallen asleep all by himself! And once he can fall asleep on his own , he will better equipped to GO BACK TO SLEEP on his own.
By leaving and coming back, you are letting him PRACTICE being alone, and also reinforcing that you will always come back for him. He will learn that its OK to be alone at night, and still feel safe and loved.
The book said it works with babies too (wish I'd have read it four years ago...).
I should also tell you that we "lost" her pacifier during this time. (well I cut one, and the other one genuinely got lost that same day). I think it was contributing to the awakenings.
The process took about 3 weeks with my two year old. It seemed like a long time then, but I'm glad we did it this way.
Best of luck to you, let us know how it turns out.