Love can be a very fickle feeling.

One moment you think you've found the love of your life, and then the next you've realized there's no way you'd want to spend the rest of eternity with them.

While love can be a an intricate, awe-empowering emotion, so can be the realization you no longer feel the same way about your partner.

According to an article written by Romeo Vitelli for Psychology Today, evolutionary psychologists have long argued that the ability to end a relationship and prepare for a new one can have definite advantages in terms of improving the ability to reproduce successfully. He said while it's common for some species to mate for life, humans generally don't.

Brian Boutwell, the associate professor of criminology and criminal justice, and epidemiology at Saint Louis University, published an article in the Review of General Psychology that suggests humans have subconsciously formed a mental mechanism - called primary mate ejection - to sever the emotional bond between romantic partners.

Boutwell's research has found opposing factors on why men and women choose to activate their primary mate ejection modules.

1. Why men end a relationship

Boutwell said a major deciding factor for men to end a relationship is based on if his partner has had a sexual relationship with another man. He reports from an evolutionary standpoint that men are intrinsically wired to avoid "raising children that aren't genetically their own."

"Men are particularly sensitive to sexual infidelity between their partner and someone else," Boutwell said. "That's not to say women don't get jealous - they certainly do - but it's especially acute for men regarding sexual infidelity."

2. Why women end a relationship

In contrast, Boutwell said a woman is typically more inclined to break up with her partner if they engage in an emotional affair. If they are unfaithful in that regard, natural selection subconsciously allows women to end their relationship in order to pursue a mate who is willing to provide them with a plethora of resources. This can range from helping to raise a child to providing physical protection.

However, Susan Orenstein, a licensed psychologist and relationship expert in Cary, North Carolina has said there isn't just one underlying factor that causes you to fall out of love.

Orenstein has noted while there may be several different factors that may lead to the demise of a relationship, there are four that tend to be the most common:

1. Couples no longer meet each other's needs

Dr. Mudita Rastogi, a licensed marriage and family therapist in Arlington Heights, Illinois, says in the beginning of a relationship, partners are initially attracted to each other's traits, but over time, they will become aware if their needs are left unmet.

For example, if a partner lacks companionship for their counterpart, or if one believes the other fails to offer any means of support, their relationship will ultimately fail..

Rastogi continues, and says the traits that may have attracted you to a partner in the first place can eventually become infuriating and intolerable, such as when one's partner charisma and sense of humor can become viewed as too loud and flirtatious. This change in opinion can lead to jealous and resentment.

2. They have left the honeymoon phase

Every relationship experiences the honeymoon phase, where partners engage in lust, excitement and pride for their counterpart.

But Orenstein says this period will eventually fade and the highs of the relationship will level out, due to how humans are wired.

According to anthropologist Helen Fisher, all cultures go through varying degrees of the honeymoon period for each couple to form a bond and inevitably procreate.

However, Orenstein says due to the fact this stage of a relationship will eventually fade, partners will be under the impression they are no longer in love, and take their significant other for granted.

We may "gloss over the positives that our mates do for us, and instead tend to focus on the negatives," she says.

3. There is a significant amount of unresolved conflict

A crucial part of any relationship is to be able to communicate with your partner. According to Orenstein, some couples may keep their emotions hidden because they are afraid of conflict. However, this tactic leads to frustration, hurt and resentment building up, which "crowd[s] out the love and joy that they used to feel."

4. Fighting is frequent and unnerving

Orenstein says couples who may have differing perspectives can often lead to a struggle for control. The partners don't know how to compromise and work together, creating an insecure and unsafe environment, and viewing each other as an enemy.

"These couples are in high-conflict relationships, often finding themselves yelling, saying hurtful comments to and about their spouse, and even becoming physically aggressive," she says. "Any feelings of warmth and affection are taken over by feelings of fear, anger and shame."

Although realizing you've fallen out of love with your partner can be devastating, there are ways you can prevent your candle of love from burning out.

Dr. Helen Fisher told CBC that the key is to never take your significant other for granted, since romantic love isn't permanent.

"One of the big mistakes that both men and women make is to wear really bad clothes around the house," she said, adding that people should never stop seducing their partner.

"Keep that courtship going. Just keep it going. We don't assume our will be around jobs forever, we don't assume we'll keep our friends forever. It's a mistake to think this person can't walk. The bottom line is don't take people for granted. It's a mistake. Not in this world," she added.

Have you ever been through rough patches partner? Let us know how you overcame it in the comments!