Literally they say in the books that the ring has no effect on Tom, it's not simping its just cannon. He would have forgotten about it and lost it because it has no hold on him and can not influence his will. It literally could not corrupt him. Every one is influenced by it to some degree just being around it, the awe and fear of the power it hold. Tom can not even think of the ring like that it's just a little trinket to him. He isn't some super strong being or anything, he just doesn't have the ability to want things like that.