Why you should never take back someone who left you for someone else

I may not be a great writer, but when I read something that appeals to me, I try to understand why.

From two comments on Reddit, in response to this post:

Nope, don't take her back. She left you just because she thought she found something better, so she'll almost definitely do it again. Go ahead and follow her idea, and find someone better than her.

This is excellent advice.  If someone leaves you for someone else — or you discover that someone already was getting their ducks in a row to make or force an exit, while keeping you 100% in the dark — that person will certainly do it again.  There are just some people who, when things turn temporarily bad, start looking for someone — anyone — who will take them so they can make their exit, leaving their partners behind.  This is, of course, extremely dishonest, but I've lived it and I've seen it happen. 

She made the choice to throw everything you had away and risk it for a guy she had a crush on for a short period of time. That was the risk she took. She should know better that you won't be there to take her back because who's to say this won't happen again? Crushes are normal while in relationships it's whether you act on it and are willing to throw everything away for this one chance. She felt that everything you had was worth giving up for this guy. Don't let her come back. She hurt you and your relationship. It'll never be the same.

I'm a girl who has had a few crushes on my five year relationship. Didn't leave my man because I love him and our relationship and everything we've shared together.

Again, supremely excellent advice.  This advice-giving woman is wise, probably beyond her years.  She describes the typical case of the pole-vault affair — well-documented in Women's Infidelity, yet not the exclusive province of women — where the cheating partner makes themself available to other people, anyone, until someone bites, giving them the attention they craved but couldn't get during a tough time in their committed relationship.

Ordinary decent people in committed relationships develop crushes all the time — the difference between them and dishonest cheaters is how they respond to the crush.

Ordinary decent people understand, and they work problems out with their partners; if there is an unsurmountable problem, they will seek to end the relationship first, before finding comfort in the arms of another person.

The cheater, on the other hand, distances themselves from their partner while making themselves available to others — that is, either signaling to or pursuing other potential partners — until someone bites.  This someone is usually an unscrupulous and desperate type, who couldn't get anyone else, not even from the bottom of the barrel.

Unsurprisingly (you'll soon get why), in that category we have people who are repulsive, who are extremely insecure, or who are frequently considered creepy by others.  This explains quite well how anyone who has seen an affair unfold, often notes how disgusting the "other person" is, compared to the cheated partner.  Look at Arnold Schwarzenegger's mistress and compare her to his wife, if you want a pretty good example of this effect in action.

If you think about it, this effect stands to reason.  This category of "other people" just can't get any good person to be with them, because they just don't have or offer the value (as people, as partners, as confidantes, you name it) that good people would instantly recognize and be attracted to.  And it's also the case that people who have affairs usually don't have many options either — decent people who feel that they are worth something wouldn't even give them the time of day.  If you think about it... someone willing to lie to and cheat on their partner, and someone who is repulsive (inside, outside, or both) are actually the perfect match for each other — none of those two are capable of giving themselves self-worth that they don't have to begin with.

Crucially, often it is said that the cheater "should not be blamed" because "it just happened", or "I couldn't help it", or "I wasn't aware that this was happening".  This is a common myth, predicated on this false belief that only Machiavellian, consciously machinated evil, qualifies as actual wrongdoing.  The truth couldn't be further from that.  It need not be the case that the dishonest person be consciously aware of what he/she is doing — on the contrary, this process is entirely unconscious.  It is only actually people who are conscious and self-aware of their feelings, that don't succumb to them, when their feelings would make them do something wrong.  It is in fact consciousness and self-awareness of one's own emotions and reactions — the subjugation of mindless animal desire to the neocortex — that is the prerequisite for self-control.  That is as true of the date-rape drug rapist as it is of the common cheater.  As a general rule, wrongdoing does not need to be consciously Machiavellian to be evil.  It just needs to be wrongdoing.

The way this Redditor ends her comment is simply perfect.  I really like it, because it speaks to my own experiences of having remained loyal even during the worst times of many of my own relationships.  I'm going to repeat it for emphasis:

I'm a girl who has had a few crushes on my five year relationship. Didn't leave my man because I love him and our relationship and everything we've shared together.

That's very much right.  This feat is accomplished daily by millions upon millions of people in committed relationships, who will face temptation everywhere they go.  This brilliant Redditor is one of them.  I have been one of them.

What distinguishes good people from low-quality people isn't how they act when they are happy and fulfilled.  It's how they respond when temptation appears.  Low-quality people lie, cheat and betray.  Good people do the right thing.

Unless you have a severe mental disorder, it really isn't all that out of the ordinary to do the right thing.