After sleeping on a bed correctly placed you will respawn next to it, destroying and replaceing it or sorounding it with blocks and removing them wont change your respawn point but if the bed is missing or obstructed when you die and then is deobstructed or replaced if broken, you will lose the spawnpoin. The only way to set your spawnpoint again will be sleeping on the bed.
I see this as an unexpected mechanic, your spawnpoint shouldnt be removed if an attempt to spawn in the bed fails because if someone wants to help you fixint the bed he wont for example in a server where you live with your team 50k blocks away
Thanks