This is the No. 1 reason people get divorced, says Emily Ratajkowski's divorce lawyer: ‘I'm in everybody's bedroom and bank account’

In her eight years practicing family law, Jackie Combs has helped her clients navigate many divorces.

As an attorney at Blank Rome, Combs represents high-net-worth individuals and celebrities like model Emily Ratajkowski and hairstylist Chris Appleton. "Many of my clients' net worths are more than $25 million," she says.

Her clients also tend to be young, mostly Gen Z and millennials.

Among the many reasons Combs has seen her clients' relationships come to an end, at the top of the list, she says, is lack of communication.

"I think that is the root of a lot of issues," Combs says. Here's why.

It's important to be on the same page about core values

The people who come to Combs for representation tend to open up to her about very personal parts of their lives and seek her advice.

"I have very intimate relationships with my clients," she says. "As their legal counsel, I'm in everybody's bedroom and everybody's bank account."

And an inability to communicate with their partners comes up time and time again.

Often, it comes down to finances. "It can look like you're not aligned on spending habits," she says. "It could look like you are not aligned on budgeting or saving plans."

For example, one party might like to go out each morning for an expensive coffee while the other prefers making coffee at home.

The conflict could also arise over other core values, such as how to raise kids or what activities to prioritize in the relationship.

If you can communicate, you can work through and weather every storm.

Lack of communication is also the top reason celebrity divorce attorney Laura Wasser has seen people break up. "Because you don't develop the communication tools when things are going well, then when things are not going well you tend to not have the ability or wherewithal to discuss them," she previously told CNBC Make It.

Wasser recommends having conversations around life decisions early on, like where to send your kids to school and if it's OK for a parent to come live with you in their old age.

Family law attorney Padideh Jafari also encourages couples to have frank conversations before marriage and ask questions like: What is your credit score? Is religion important to you? And should we consider a prenup?

Ultimately, "if you can communicate, you can work through and weather every storm," Combs says.