You can’t help who you fall in with—and in some circumstances, you can’t help where your love interest lives either. But if you’re applying for security clearance, there’s more to consider before entering into a long-distance relationship than higher transportation costs: A long-distance love affair could cause problems during the application process and keep you from getting clearance.

When you apply for security clearance, you’ll fill out an SF-86. On that document, you’ll be asked questions about foreign contacts—which is one way the agency will find out whether you’re trustworthy, says Charles McCullough III, a partner at Compass Rose Legal Group and former Inspector General of the Intelligence Community.

“Part of being trustworthy is that they ask themselves, ‘Are you loyal to the U.S.,’” McCullough explains. “But even more importantly—or more specifically—they ask themselves, ‘Is there a conflict of interest here? Is there a conflict because you have a relationship with somebody who is living overseas—and by virtue of that romantic relationship, do you have a loyalty to that person or country that may negatively affect your ability to keep secrets close here in the U.S.?’”

The agency will want to know how often you travel to visit your significant other, and depending on the country, that may (or may not) be significant. Certain countries, McCullough says, can be red flags on an application. (And you can likely guess with accuracy which countries those are.)

If your significant other has ties to the country’s government, that can cause issues, too. “If your boyfriend has contacts with people who are working for other governments, those are something you have to account for,” McCullough says. Even if your significant other doesn’t work for the government, problems can arise: If they have family members or friends who work for a foreign government or have even attended a government party—like one at an embassy—issues can arise.

If you send money to a significant other in another country, consider that a red flag, too: “Any ties you have with any other country are going to be examined fairly closely,” McCullough says.

You’ll have a chance to explain why your significant other lives abroad during the interview process, he says. If your significant other works and lives on an American reservation, for example, there likely won’t be a problem. “But if you are dating someone who decided to go and teach in a different country for a year or two, then that can get problematic,” McCullough warns.

Be prepared to answer a lot of questions. You may be asked not only why your significant other lives abroad, but detailed questions about their life, such as where they attend school, if they’re studying abroad; and who they live with, if they have roommates, and what those roommates do for a living. “It’s seven degrees of separation,” McCullough says. “It can be very complicated.”

Your significant other is also likely to be interviewed. “It depends on how close the relationship is,” McCullough says. “They’re not clearing [your significant other], they’re clearing you—but they may want to interview your [significant other] as part of the process. That’s very common.”

One thing you can do to protect yourself? Don’t open bank accounts in the country where your significant other lives.

“You don’t want to do anything to establish yourself as a resident or any permanency in that country—especially if it’s just a relationship with a boyfriend or girlfriend,” McCullough says. The rest, McCullough says, comes down to honesty and transparency during the interview process.

“What they’re looking for when it comes to foreign influence is: Is there some reason to think you have a conflict of interest?” he explains. “Is there some reason to doubt your loyalty to the U.S.? And if the person with whom you’re having a relationship is a non-U.S. person—a foreign national living in a foreign country—and you’re making trips back and forth and back and forth, that’s going to be more problematic than if the person is a U.S. citizen and they’re just over in the foreign countries on a deployment or for some sort of stint that they’re doing for a university, or whatever the reason might be. That’s going to be less problematic.”