I figured his real totem was his wedding ring. Could be wrong, though.

 

I"m not sure they ever explained to saito what a totem was or why no one else should touch your totem, I thought that by knowing it's balance it automatically ruined the totem.

 

Someone knowing the balance means they could recreate it in a dream. Making a dream all the more effective as they'd think it truly was reality. But as you said Saito never got an (onscreen) explanation of totem's. Saito has no reason to trap Cobb and if some unnamed party wished to do so, there are far less convoluted methods.

 

I may be wrong, but I think it didn't make any difference as it wasn't a real totem, so Saito still wouldn't know how it should "feel" to make Cobb believe he is in the real world.

 

Wait a second, I just realised something. Cobb's totem is Mal's old totem, and Cobb has a somewhat-autonomous projection of Mal inside his head. Could Mal have been fucking with his totem in the dream world since Cobb's idea of Mal would obviously include her knowledge of what the totem's balance was?

 

She could have been fucking with his totem the entire time then... from the very beginning.