So why exactly did he do it?
Out of canon answer
From a plot perspective, something has to drive Anakin to the dark side. Why use character development when you can have
no character development and stupid characters Jar Jar?
Having a Jar Jar like influence around someone's youth traumatized Anakin. Jar Jar was around for a large amount of his formative years and a constant irritant. He worked closely with Anakin and Palpatine during his youth and childhood while Palpatine gained influence with Amidala. This influence eventually is enough that when the moment was right, Jar Jar could suggest the following
It's a clear desa Separatists made a pact witha desa Federation du Trade. Senators! Dellow felegates! In response to this direct threat to the Republic, mesa propose that the Senate give immediately emergency powers to the Supreme Chancellor!
From a plot perspective, a character such as Jar Jar was needed - no one would believe anyone else could suggest such things. A stupid, easily manipulated senator was required. This is why Palpatine had been building a relationship to manipulate him and ultimately control him. The secondary purpose is that by keeping Jar Jar around Anakin for his childhood, he is wearing Anakin down, making him more vulnerable to the eventual turn to the dark side. Being forced to be around Jar Jar makes Anakin angry and during his Jedi training, burying these feelings results in a deep well of anger Palpatine is filling for years.
Anakin is forced to turn to Amidala in light of the trauma he is forced to go through during his childhood due to Jar Jar. This is necessary in order to make Anakin's terrible relational dialog
make any sense at all only slightly less bad. These repressed memories drive him seek relational comfort and consolation from Amidala, because she too has experienced the horrible effect of Jar Jar. The absolutely awful dialog conversations they have are a result of his repressed childhood memories, her interactions with Jar Jar, and his attempts to cope with these memories.
This repression is ultimately fulfilled when Vader allows Tarkin to blow up an entire planet just to get rid of Jar Jar.