I found the answer:
But we use personal pronouns, not reflexives, after prepositions of place... Source
He had a suitcase beside him.He had a suitcase beside him.
and after with when it means "accompanied by":
She had a few friends with her.She had a few friends with her.
After a preposition of place or location we use a personal pronoun and not a reflexive pronoun. Source
He put the backpack next to him.He put the backpack next to him.