Saving into two tables using multiselect

After the patchEntity, result is:

‘products_accessories_categories’ => [
(int) 0 => object(App\Model\Entity\ProductsAccessoriesCategory) {

  	'products_accessory_id' => (int) 1,
  	'products_item_id' => (int) 2,
  	'[new]' => false,
  	'[accessible]' => [
  		'products_accessory_id' => true,
  		'products_item_id' => true,
  		'products_accessory' => true,
  		'products_item' => true
  	],
  	'[dirty]' => [],
  	'[original]' => [],
  	'[virtual]' => [],
  	'[hasErrors]' => false,
  	'[errors]' => [],
  	'[invalid]' => [],
  	'[repository]' => 'ProductsAccessoriesCategories'
  
  },
  (int) 1 => object(App\Model\Entity\ProductsAccessoriesCategory) {

  	'products_accessory_id' => (int) 2,
  	'products_item_id' => (int) 2,
  	'[new]' => false,
  	'[accessible]' => [
  		'products_accessory_id' => true,
  		'products_item_id' => true,
  		'products_accessory' => true,
  		'products_item' => true
  	],
  	'[dirty]' => [],
  	'[original]' => [],
  	'[virtual]' => [],
  	'[hasErrors]' => false,
  	'[errors]' => [],
  	'[invalid]' => [],
  	'[repository]' => 'ProductsAccessoriesCategories'
  
  },
  (int) 2 => object(App\Model\Entity\ProductsAccessoriesCategory) {

  	'products_accessory_id' => (int) 3,
  	'products_item_id' => (int) 2,
  	'[new]' => false,
  	'[accessible]' => [
  		'products_accessory_id' => true,
  		'products_item_id' => true,
  		'products_accessory' => true,
  		'products_item' => true
  	],
  	'[dirty]' => [],
  	'[original]' => [],
  	'[virtual]' => [],
  	'[hasErrors]' => false,
  	'[errors]' => [],
  	'[invalid]' => [],
  	'[repository]' => 'ProductsAccessoriesCategories'
  
  }

],

but i selected only one item, but show 3 items from stored db… not aplicated my selected items.