You gradually and gently taught him to sleep without being breastfed. You can follow exactly the same mentality for learning to sleep without you. Slow, gradual, gentle.
Whatever you do now, make tiny changes towards independent sleeping.
If you currently snuggle right up to him, try snuggling just your head close to his and a hand on chest, but body angled away from his.
If he will tolerate that, try getting him to sleep with just your hand on him for reassurance. Then remove hand when settled (but put back if unsettled), but stay lying next to him, face to face, but not touching.
When he'll tolerate this start turning your body so you are not face to face. Try facing the ceiling. Then rolling to face away from him.
This is a key stage. Maintain for a while where you can put him down in the bedside cot, but roll over yourself and face away from him. But stay there as a presence until asleep.
Then roll to the edge of the bed, far away from the cot. Then sit on bed facing away as he goes to sleep. Then stand by the bed. Etc. All the time moving towards teaching him that he'll be put to bed then you will withdraw yourself as he goes to sleep.