In the script of Episode III I read there was an early scene where Obi-Wan stopped by to talk to Padme about Anakin. This leads to Anakin to question "Obi-Wan's been here, hasn't he?" I kinda left no doubt in my mind that Anakin suspected that Padme was having an affair with Obi-Wan and when he saw him appear at the top of the ramp of Padme's ship that was the clincher in his conspiracy theory.
there are so many things that lucas could have done. i really dont understand why he had the ten year old ani. The whole TPM plot was irrelivent to the overall story and doesnt even link well into episode II. And then lucas creates this mysteriouse character named Sifo Dyas in episode II, who is never revealed in episode III.