Conserving rotational momentum

So lets say I rotate my object on its y axis, If I then make it rotate on its x axis, it’ll stop rotating on its y axis completely. How do I conserve the momentum?

Here’s the script I’m using:

function FixedUpdate () {
if (Input.GetKey(“left”))
{
rigidbody.AddRelativeTorque (Vector3.up * -10);
}
if (Input.GetKey(“up”))
{
rigidbody.AddRelativeTorque (Vector3.forward * 10);
}
}

Add Time.deltaTime to your equation like the following.

function FixedUpdate () 
{
    
    		if (Input.GetKey("left")) 
    
    		{ 
    
    			rigidbody.AddRelativeTorque (Vector3.up * -10 * Time.deltaTime); 
    
    		} 
    
    		if (Input.GetKey("up")) 
    
    		{
    
    			rigidbody.AddRelativeTorque (Vector3.forward * 10 * Time.deltaTime); 
    
    		}
    
}