My boyfriend recently got an Instagram n doubt he wants me to find out?

[LoLo]

Okay so i know he would not like me having one...2 yrs ago we deactivated out fb accounts as he suggested. I told him i was ok with us having it as long as we continued to be friends. He didn't agree n said if i had it, he'd have it too but would unfriend me. I decided to deactivated just to avoid problems n i also know social media sites can cause problems in a relationship so i deactivated it. Once when a friend sent me a snapshot of picture from her Instagram he was upset cus he thought i had an account .. There's something wring here right ? Why dies he think it's ok for him to have one? I dint mind him having one as long as he doesn't mind having me as a friend. How do i approach the situation without causing an argument ?