Toddler sleep

y almost 3 year old boy has been so clingy to me for months now. He wont go to his daddy or anyone. Even if i leave the room he has to follow me. But it's especially hard at bed time. He wont fall to sleep unless I'm laid on his floor at the side of his bed. He screams the house down if I leave him to fall asleep alone. Once he is asleep I leave the room. But then 2/3/4 hours later he comes crawling into my bed. I've tried putting him back to bed but he starts screaming again if I leave him or even if I stay by his bed he wont go to sleep. I feel like I've tried absolutely everything and I dont know what to do. It's getting in the way of my relationship with my partner also as we arent able to sleep together as our little boy is in our bed. It doesnt matter through the week as my partner works nights shift anyway but still! I need help😂