Everyone's an expert on relationships.
Your coworker, who overhears you fighting with your partner on the phone; your great aunt, who found out from your grandma that you and your girlfriend just moved in together.
Except most people are not, in fact, experts on relationships. The things they insist are terrible for you and your partner — like, say, fighting and cohabiting — are often not so bad.
Below, Business Insider has rounded up a list of myths about romantic relationships. Drawing on scientific research and expert opinion, we explain why they're not always true — and what you should know instead.
1. Fighting with your partner
The No. 1 thing successful couples have in common is their ability to repair their relationship after a fight. That's according to John Gottman, a psychologist and cofounder of the Gottman Institute.
Note that Gottman didn't say successful couples never fight. Instead, he told Business Insider that conflict is an inevitable part of any romantic relationship — but Americans in particular have a hard time accepting that.
Instead of fearing conflict with your partner, think about how you could approach it differently to make it less catastrophic.
Gottman told Business Insider: "In really good relationships, people are very gentle with the way they come on about a conflict," Gottman says. "They don't bare their fangs and leap in there; they're very considered."
For example, he said, "Instead of pointing their finger and saying, 'You a--hole!,' they say, 'Hey babe, it's not a big deal, but I need to talk about it and I need to hear from you.' In bad relationships, it's, 'You're defective, and you need therapy.'"
2. Marrying someone who's as ambitious as you are
There's no question that a relationship in which both partners have lofty career aspirations will be hard. But it won't, despite common misconceptions, be impossible.
According to Joann Lublin, management news editor at the Wall Street Journal and author of "Earning It," the key is talking about your individual professional ambitions before you get married or get serious, and hashing out a tentative plan for accommodating both parties.
Before Lublin married her husband, they signed a "marriage contract." In the book, Lublin explains that the couple hired a lawyer to draw up a contract in which they agreed that they would alternate who took the lead in any relocation for a job. (They were both planning for careers as journalists.)
Lublin told Business Insider that a marriage contract isn't necessary for a successful marriage — and it's not the cure-all for marital discord. But communicating about your professional priorities is key.
3. Occasionally wanting out of the relationship
In her 2015 book, "The Real Thing," former Washington Post weddings reporter Ellen McCarthy summarized the findings of a researcher who interviewed hundreds of married women: "The collective wisdom seems to be: 'Sometimes you will be miserable. This is the reality of long-term intimacy. Carry on.'"
In other words, if you expect to be really happy all the time when you get married, you're setting yourself up for disaster.
McCarthy also explained the similar perspective of a marriage educator:
"[Diane Sollee] wants couples who are getting ready to walk down the aisle to know — really know— that it will be hard. That there will be times when one or both of them want out and can barely stand the sight of each other. That they'll be bored, then frustrated, angry, and perhaps resentful."
She added: "Diane also wants them to know that all of these things are normal."
However, if you're unhappy all the time, you might want to consider whether the relationship is healthy, and/or seek the help of a professional. It's really about learning to take stock of the relationship as a whole.
4. Keeping your finances separate from your partner's
Your friends and family might raise their eyebrows when you tell them you're keeping separate bank accounts — but it doesn't necessarily portend relationship disaster.
Thomas J. O'Connell, president of International Financial Advisory Group, Inc., told Business Insider that there are a number of logistical reasons why couples might choose not to merge their finances.
For example, maybe you're blending families, and one or both partners are bringing children from a previous relationship. Sometimes parents who have gotten divorced are legally required to set aside money for child support or a college fund, so they can't share that money with their new spouse.
Other reasons for keeping separate finances are more emotional. For example, Michael McNulty, a certified Gottman relationship therapist, said if someone came from a family in which money caused major problems, they might be more fearful about letting someone else share control of their finances.
Regardless of whether you choose to combine finances or keep them separate — and this is key — McNulty said it's crucial to have an ongoing dialogue about it.
5. Sharing a home with your partner before getting married
Some research suggests that couples who live together before marriage — i.e. couples who cohabit — are at greater risk for divorce and marital distress.
But that doesn't necessarily mean that your relationship is doomed if you move in with your boyfriend today.
One theory put forth by researchers at the University of Denver is that many couples who live together wind up getting married out of inertia, and not because they genuinely want to. Finding a new apartment or making a shared-custody plan for a pet might seem harder than getting hitched.
On the other hand, if couples are committed to a future together before they move in, there's a smaller chance that they'll find themselves in an unhappy marriage.
6. Not having sex all the time
Focus on quality over quantity. At least, that's the advice from George Loewenstein, a professor of economics and psychology at Carnegie Mellon.
As Business Insider's Jessica Orwig reported, in 2015, Loewenstein and his colleagues published the results of an experiment in which they told some married, heterosexual couples to have sex twice as often.
As it turns out, couples who doubled the frequency of sex were in fact less happy than couples who weren't given any such instructions.
The researchers surmise that's because being told to have sex more often took away the fun of it — it became a chore. So don't try to have sex more often just for the sake of having sex more often; instead, try to make your sex life enjoyable.
7. Marrying someone who doesn't meet every single one of your personal needs
Northwestern University social psychologist Eli Finkel and colleagues have documented a curious historical trend related to marriage.
As Orwig reported, whereas we once expected our spouses to keep us safe, provide for us, or be our companion, we now expect our spouses to fulfill deeper needs, like self-esteem, self-expansion, and personal growth. And we're often disappointed.
One potential solution is to seek additional fulfillment outside the relationship — from friends, work, or hobbies, for example. While it would be great if our spouse made us feel like the best version of ourselves all the time, it might be more realistic to rely on other outlets to make us feel that way, too.
SEE ALSO: 10 myths about dating too many people believe
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