Damon: elena and Katherine. No matter how many times he says your the only one he loves you still have doubt.
Stefan: caroline. You know him and caroline had a thing together before he met you.
Kol: Davina. No matter how many times he reassures you he was only using her, you can't help but be jealous.
Klaus: cami. Klaus seems to always listen to what she says, but never listens to you.