Spying on a significant other while in a relationship is morally questionable, but that's not to say people don't do it. In fact, most women admit that they check their significant others' phones and emails if given the opportunity for reassurance. And it's not just women, as men have admitted to doing the same. In an age where 70 percent of married men admitted to cheating on their wives, it is no surprise that someone would come up with a way for women to find out if their significant others are cheating.

In Brazil, a new app has been downloaded by thousands to their smartphones from the Google Play app store last week. The app has since been removed from the Google Play app store after many people have complained about the privacy abuse and how the app can be used improperly for extortion or stalking. When asked about removing the app, Google spokeswoman Gina Johnson reportedly said that their company policy prohibits them from speaking about why apps are removed. Here are four things to know about the boyfriend tracker app:

1. The boyfriend tracker app is called "Rastreador de Namorados," which translated to boyfriend tracker in Portuguese for Boyfriend Tracker. "Brazilians are a jealous people, what can I say? Of course it's going to be popular," said Marcia Almeida, a 47-year-old woman in Rio whose marriage ended due to her husband's infidelity, to USA Today. Many have pointed out that Brazilians were furious over the NSA surveillance in their country, yet the citizens are okay downloading this app to do the same thing. "It's a different type of spying," said Marcia Almeida of comparisons to the NSA surveillance program. "You're checking up on somebody you know intimately, not some stranger."

2. Rastreador de Namorados, according to its website, promises to act like a "private detective in your partner's pocket." What are its functions? It allows an person to track updates on their partner's location, sending duplicated of text messages to their phone and even allows a command to let the target phone silently call their own phone to allow for eavesdropping. Given the functions, many critics of the app have pointed out that it could be used for stalking and violate privacy rights.

3. Similar apps are marketed for smartphone users in other countries, including Europe and the U.S., but Boyfriend Tracker is the first that has made any impact in Brazil, a country still irate as it learns more about Washington's snooping. Brazil has sent a government delegation to meet with U.S. leaders about the spy program that was revealed by Edward Snowden, the former NSA contractor who has been on the run since May and was recently granted asylum in Russia. Others point out that it breaks Brazil's anti-online harassment and hacking law. That said, there are similar apps on the Google Play market for parents to monitor their children's phone.

4. Matheus Grijo, the 24-year-old Sao Paulo-based developer who created the Boyfriend Tracker, has revealed that since it was launched two months ago, the app has lured roughly 50,000 users. According to Matheus Grijo, a lawyer looked at the app and concluded that it does not violate Brazilian laws. As such, even though the app was removed from the Google Play app store, it is still available for download on the company's website with a disclaimer. The disclaimer reads that the app is for "social and recreational use" and that developers are not responsible for any misuse. "We are waiting for Google's position on the removal of 'Boyfriend Tracker' from Google Play, which we consider an error," read a posting on a Facebook page Grijo set up for the app.

Wondering how you work the app? The suspicious partner has to get the phone of their significant other and upload the app. While the free version of the app leaves the icon visible, a $2 version keeps the icon invisible for a month. "In Brazil, we have this culture of switching partners really quickly, so this is a way of dealing with that," said Grijo. "People really appreciate having a tool to help them find out whether they're being cheated on." Cheating is a two-way street, as women are equally as likely to cheat as men, but most of the marketing is catered towards women who are suspicious of men.