A relationship therapist breaks down the 10 most common fights couples have

When unmarried couples come to see Sussman, they often want to talk about commitment. Typically, Sussman said, one partner feels like they're more committed than the other. Or, one partner wants to "move the relationship forward" by moving in together or getting engaged and is encountering some resistance.

If couples are fighting about household chores, Sussman said, it's probably because "one person feels like they're taking the lion's share of the work."

In Sussman's experience working with heterosexual couples, that person is usually the woman. Meanwhile, she added, "I often hear the men feeling that they're doing a lot but they don't get credit for it. They get picked on a lot."

Indeed, according to a 2007 Pew Research poll, sharing household chores is the third most important factor in a successful marriage. (The first two are faithfulness and a happy sexual relationship).

And in an excerpt from "Fast-Forward Family" published 2013 in The Atlantic, three researchers write that even today, women still tend to shoulder the brunt of their family's housework.

Sussman said she's seen a spike in the number of complaints about a partner's social media habits in the last five years. Typically, couples with these kinds of problems are in their 20s and 30s.

One person might complain, for example, "that their life is plastered all over social media or they think their partner is addicted to their phone." Sussman's also heard from people who are worried that their partner is following a ton of models on Instagram.

Another common issue? Staying in touch with an ex on social media.

"It's very normal in a couple that one person is a spender and one is a saver," Sussman said. The problem is "you think you're justified and the other person is at fault." The saver might accuse the spender of being fiscally irresponsible; the spender might accuse the saver of being cheap.

Don Cloud, president and founder of Cloud Financial Inc., previously told Business Insider that he frequently works with spender/saver couples. The first step, he said, is for each partner to share their beliefs and feelings about money.

Yet Sussman said issues also tend to arise when couples move in together or get married and face the decision about whether to combine finances, a notoriously difficult choice. If they're hesitant, "might this show that there's a lack of trust?"

Or, fights about money might come up later in a relationship. Maybe both partners worked when they started dating, but once they had kids, one partner stayed home. The partner who works might be "holding that over [the other partner's] head," or even engage in financial blackmail, Sussman said.

"Someone might be a workaholic," Sussman said, "or someone might be prioritizing work over relationships."

As Michael McNulty, a master trainer from The Gottman Institute and founder of the Chicago Relationship Center, told Business Insider's Rachel Gillett, "Having a spouse addicted to work can feel like as much of a betrayal as extramarital affair to the other spouse."

Sometimes people bring their partner to see Sussman because the partner has an alcohol problem — or at least the person perceives it that way.

As it turns out, one small study, published 2013 in the journal Couple and Family Psychology, found that substance abuse was a common "final straw" in the decision to get divorced.

Sussman says she sees a lot of couples with small children who aren't finding enough time to connect with one another. Sometimes they feel "their relationship has become very transactional."

Scientists who have studied the transition to parenting say there are three factors that help a copule maintain intimacy after having a baby:

• "Building fondness and affection for your partner"
• "Being aware of what is going on in your spouse's life and being responsive to it"
• "Approaching problems as something you and your partner can control and solve together as a couple"

Sometimes one partner wants sex more than the other, Sussman said. Or, a couple tells her they're "feeling that their sex life has died."

Bat Sheva Marcus, the sexual dysfunction specialist and clinical director of The Medical Center For Female Sexuality, previously told Business Insider about the usefulness of a "sex schedule," which is exactly what it sounds like. "If you want to have sex, you need to schedule sex," Marcus said, especially when both partners are busy, or when they have different desire levels. "That doesn't make the sex any less special."

This is something Sussman said she sees "plenty of" in her practice.

While the discovery of an affair can potentially destroy a relationship, it doesn't have to. Couples therapist Esther Perel previously told Business Insider that couples can sometimes become closer and more honest with each other in the wake of infidelity, almost as though they're entering into another marriage.

A common parenting problem Sussman sees is that one parent is more lenient and one parent is stricter.

That's why Carl Pickhardt, a psychologist who's written multiple books about parenting, previously told Business Insider that the No. 1 question you and your partner should discuss before having kids is: How do you manage joint decision-making?

"If you have parents who have a hard time bridging disagreements," Pickhardt said, "that's probably not a great sign. They've got to be able to know how to communicate, and how to change, and how to make concessions, and how to compromise."

"Too much bickering will wear down any relationship," Sussman said. "I've heard people say, 'This relationship ended by death by a thousand paper cuts.'"

That's why she makes the following recommendation: "If you're going over and over again about something and you can't seem to create a solution, go see a couples counselor — not to solve the problem, but to learn the skill set so you can do a better job of working through these conflicts as they come up in your life."