We're told to be wary of the green-eyed monster. That insidious thing that can creep up out of nowhere and knock you for a six -- at times when you may least expect it.
Whether it's your best friend's job promotion or your ex's new fling, it can also confuse the hell out of you. And proceed to do damage.
If you let it.
The Huffington Post Australia spoke to behavioural expert Dr John Demartini to put all of your confusion and worries to rest.
Why do we feel it?
First things first, you're not totally crazy. We're all hardwired to feel jealous.
"Biologically speaking, inside the central part of our brain, we desire certain things. And we search for prey and try to avoid predators. That is our basic primary 'reward and punishment' system," Demartini told Huffpost Australia.
Jealousy is a biological, built-in system for fear of loss of something that we value.
"Anything reminds us of prey -- which supports what we value -- and anything that reminds us of predator -- which challenges what we value -- we have biological impulses to move towards or away from them."
We're talking anything from food and intelligence to ambition, resources or social skills. And then there are those good ol' relationships.
"Jealousy is a biological, built-in system for fear of loss of something that we value," Demartini said.
"We run the risk of losing our partner or our job, and our subsequent protection or security, if someone or something comes along with more of those powers than we think we have. There's a natural yearning there. And so we react."
Contrary to popular belief, jealousy is a sign that you value the relationship or friendship. So whilst it may have dire consequences, it is rooted in a desire to protect what is important to you.
And then there's envy.
Whilst they're often bundled together, jealousy and envy are different emotions -- although they sometimes overlap.
Think of envy as the gap between what you have and what another person has.
"People may envy others who have more money or success, but there's no jealousy there because they don't attach that with any fear of loss," Demartini said.
You can be envious of a job position and jealous of someone who grabs it.
"Envy could be some of the components that you are jealous of. You may be envious of someone who you think is more attractive than you but not jealous because your partner isn't showing any sign of threat," Demartini said.
"The second you meet someone who you think has more to offer them than you do, jealousy creeps in."
Are we too insecure?
According to Demartini, insecurity exists only as a fear of losing something that we don't have.
This also comes down to past experiences.
"If you feel like you've been jolted from somebody else, you're most likely going to carry that anxiety forward into your next relationship -- possibly creating pre-emptive strikes that aren't even real," Demartini said.
"There many be no need for jealousy but they may have all of these associations from past relationships."
Should we trust it?
Jealousy can be self-deprecating disaster waiting to happen -- or we can choose to use it wisely.
Wake up to it.
How so, I hear you ask. Easier said than done, right?
"With any kind of jealousy or envy that you may have, let that be a reminder to find out what you see in that person or thing in yourself," Demartini said.
I spoke with a woman who was very angry and resentful as a consequence of her jealousy towards another woman who was trying to win over partner. I asked her what specifically this other woman demonstrated as a power that she didn't think she had. She said it was her youth. So I asked her what it is that she had as an advantage with her age.
We stacked up the benefits of her age and her experience until she saw herself as equal. Once she empowered herself, the woman lost all of her power and she claimed it back.
"It can be used as a wake up call to identify what we're not acknowledging in ourselves."
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