Hi, I am Dave, I will help you with this.
You can use your Microsoft account on many devices, that will not cause any problems.
With regards to activation, a Windows licence can only be used on one device at a time, unless you have retail licence keys associated to your Microsoft account online, then Windows should not activate automatically, and what may happen is your licence will be moved to the new device you log into, and if that is what happened, the original device will deactivate after some time.