The King of Cups reversed is highly emotionally manipulative and controlling. This is someone who is sulky, toxic, moody, and withdrawn from others, especially if things do not go his way. He can be vengeful and has a talent at being able to punish others through emotional manipulation. He leaves you feeling uncertain about yourself and as if you are the problem, not him. This only leads to emotional instability within you, which is completely undeserved.
A reversed King of Cups can also represent a loving and mature, emotional person, who has let their emotions take control of their life. The King of Cups may depend too much on others and view himself through the eyes of others. He may fall into delusions or alcoholism, or others forms of escapism to deal with emotional pain. This could show you trapped in a relationship with someone that is dependent and emotional, or a co-dependency situation.
In a relationship reading, the reversed King of Cups suggests that you feel really confused about your relationship and your emotions are out of control and out of balance. You are uncertain about your true feelings, and every day they seem to change which results confusing for you. You need to be careful, too, about the messages you are sending to your partner as he or she may become easily confused. It is probably best to keep some distance until you work out your feelings and get hold of your emotional state.
Finally, the reversed King of Cups suggests that you need to take greater control and responsibility for your emotional state. You want to take charge of your life but then you are waiting for the Universe to show you the way. You need to be more accountable for your emotional well-being.