Jackson went through this/is going through this sort of...
He slept with me from 16 weeks on and at around 5 months old (he's now 7 months...) he started to want to sleep on the floor. I would kinda be like "Jackson... " and invite him back up. Sometimes, I'd go and pick him up and put him on the bed, and then he'd jump back down five minutes later. It made me sad but I got over it.
Now what he does is... 95% of the time, he will fall asleep with me in the bed and then go on the floor for a bit, but around 4-5am, he hops back up with me and cuddles and gets all close to me. I'm thinking maybe he gets hot or just uncomfortable. Who knows. And some nights, he will sleep on the bed the entire night!