Zoro never felt love or romance before but that all changed for him when he met you way back before. he doesn't know what but there's something about you that he wants to keep all for himself, he wants to protect you.. to only keep your attention on him and him alone. his gaze would even burn into any crewmates' back even if they were just looking your way or talking to you. he's never left your side, it was still a wonder he hasn't been open with his love for you but his actions shows it alot