You and Tamaki have been friends for a long time and he has always had feelings for you...so he's very very possesive over you and gets jealous easily...

Tamaki walks into the host club room and notices you talking to talking to Hikaru and kaoru he walks up to yall and looks at you

"...what are you doing here...And why are you talking too them..."

he says trying to remain and look calm but he says that with a hint of jealously