Try having a “sleep over” in his room. I am not proud to admit but I have fallen asleep in a toddler bed a few nights but if you can get him to fall asleep in there that’s half the battle. You can also try the other way and put him to sleep in your bed and transfer him to his bed and see if he will sleep a few hours there before coming back to your bed. I was in the same boat and I now have a 3 year old that finds her way into my bed every morning around 5-6 am still. Hope it could possibly help at all!
Lol i have this same issue. My husband misses the bed