My boyfriend doesnt like showing me public displays of affection and it bothers me. what should i do?

he only kisses and holds my hand in private. like how am i supposed to feel comfortable and secure when he's acting like this. i would feel more at ease if he showed a little more public display affection. like this is the kinda BS that makes me feel totally insecure and i hate this feeling. i believe there is no excuse. does he have a sideline chick, tf? girls are already ogling him and they need to know he's MY boyfriend and im not sharing