Lately, I have been thinking about a friend of mine named Tony.* Tony was a gorgeous man who recently found himself back on the singles market. He was married to a gorgeous woman named Sasha.*

Sasha was initially attracted to Tony for all the right reasons. Along with being handsome, he was hardworking, passionately involved in his hobbies, and also liked to help out around the house. He was a totally functional adult and he also romanced her.

I remembered when she broke up with him and I asked her what happened. She looked uncomfortable for a moment and then said, "Well, he changed."

It got me thinking about a quote I recently heard.

I recently heard a dating coach say this, and it’s fairly true. It rings true in a wide range of different breakups:

"If you want her not to leave, keep doing what you did to win her over."

Yes, it applies to all genders — male, female, nonbinary, and intersex.

RELATED: How The Happiest Couples Survive When One Person Changes (& The Other Doesn't)

Like many others, Sasha experienced what is known as a bait-and-switch.

Did you ever notice how many people will put on a façade just to get a date? Yep, I did too. It’s a common issue and it’s one I’ve most commonly seen with two different groups of people:

• The self-proclaimed "Nice Guys" who flip out and lash out at women at the slightest hint of rejection. Most women have met at least one man who did this. It’s vile and it’s actually quite terrifying to see how many people will blame the woman for rejecting this abusive type of dude rather than blame the guy.
• The "righteous and pure" girls immediately turn into financially abusive users when they find a man. I can think of at least three examples of "family women" who did this to my guy friends. One lost $100,000 of his own personal items, another ended up having a meltdown after selling blood for food money, and a third ended up in jail after a bender. It’s … awful.

Of course, you don’t have to fit into these extreme examples to make it a bait and switch. Sometimes, it’s a matter of the person who just stops romancing his wife, or the wife who stops pulling her weight.

At one point or another, a lot of breakups happen because one partner looks at the other and can no longer recognize the person that they fell for looking back at them.

RELATED: Why Change Is Always Inevitable In Your Relationships (And How To Cope With It)

Admittedly, change can be good.

People who have experienced serious change can come out better for it. For example, the woman who loses 100 pounds is going to feel better and live longer because of it. The guy who starts a new hobby will have a richer life for it.

For the most part, change to become better is a good thing. It makes you a better partner and also makes it easier for you to make a better life for both of you. A rational partner will never hate you for becoming better while you stay with them.

However, there’s a downside to this that people rarely want to admit to seeing…

A lot of partners change for the worse when one changes for the better.

My mom’s friend, Miss Katie*, had a really bad divorce. Her marriage was wonderful when she was a high school graduate like her husband. When she went back to college, her man started to get upset and insecure.

Eventually, it got to the point that he was drinking excessively, was emotionally abusive, and turned into a royal terror to everyone around her. It was bad. Like, really bad. The divorce was acrimonious, and it’s still the stuff of legends today.

What’s sad is that Miss Katie’s husband lashed out like that because he was worried Katie was too good for him now that she had a degree. The truth was that if he hadn’t changed his behavior, they’d be together to this day.

A lot of people turn abusive when their partners do a lot better than them.

Whether it’s a matter of breaking their legs to prevent them from walking away or lashing out because they feel insecure doesn’t matter. It’s still a negative change — and it detracts from the behavior that made that person fall for you in the first place.

RELATED: 16 Signs He's Not Putting Enough Effort Into Your Relationship

Everyone falls for someone for a reason. Are you keeping that reason alive?

It’s not just about falling for a handsome face or a pretty figure. Looks get your foot in the door, but they won’t keep you there. It’s also about the content of your character and how you behave.

Think about the kinds of things your partner would say about you when you first got together. Was it your kindness? Your hardworking attitude? Your sense of humor? Your empathy? Was it because she or he felt safe around you?

When we are with someone for a long time, we forget to court them. We take them for granted. Sometimes, we can’t handle their changes or we change for the worse. That can kill even the strongest of relationships.

Keep dating your partner. Keep showing that side of you. Don’t get complacent with your partner footing most of the effort. That alone can prevent more breakups than you could ever imagine.

*names have been changed

RELATED: The Make-It-Or-Break-It Factor That Disappears First In A Relationship & How To Get It Back

Ossiana Tepfenhart is a writer whose work has been featured in Yahoo, BRIDES, Your Daily Dish, Newtheory Magazine, and others. 

This article was originally published at Medium. Reprinted with permission from the author.