Liu Siyao and her boyfriend, Guo Yuze, have been together since they were 11. They went to the same middle school and high school in Beijing.

Millennials in China's major cities were exposed to Western culture from early on. They grew up with McDonald's, Kobe Bryant and The Backstreet Boys. They celebrate two Valentine's Days: the Chinese Qixi Festival on the seventh day of the seventh month on the Lunar Calendar and Feb 14.

The Western Valentine's Day has become one of Liu and Guo's favorite holidays since they started a long-distance relationship in 2011, when Liu moved to the US to pursue her undergraduate studies at New York University while Guo attended Peking University.

"We seldom celebrate festivals together, because there are very few of them in common between China and the US," Liu said. "Festivals often mean vacations for others. But for couples in long-distance, cross-border relationships, festivals usually mean the other person's vacations."

"On Chinese New Year, while he was like 'I am gonna stay in bed for the next seven days ha ha ha!', I was like streaming the Spring Festival gala alone in the middle of the day and wiping tears on the other side of the phone," she said. "Those festivals were there only to remind us how far we are from each other that even a hug is luxury."

However, Valentine's Day is different for them, as it is a holiday celebrated by both cultures.

"The long-distance relationship makes it even more important for us to show the other one that the true love has never faded away despite the thousands of miles in between," Liu said.

Each year, they would watch a movie or an episode of The Big Bang Theory, their favorite TV show, while making a video call.

"It feels like we were face to face across the table and watching the same thing," she said. "And he would send me gifts and flowers."

In contrast to Americans who are spending less on Valentine's Day — spending is expected to drop 7.6 percent, according to the National Retail Federation — Chinese are paying more for romance.

Luxury flower brands have developed huge followings in China. On the popular Roseonly online store, 19 red roses are priced at 1,999 RMB ($290 USD), whereas they would cost about $150 in a flower shop in New York City.

The expensive roses arrive in branded boxes that many Chinese girls take photos of and post on social media.

For long-distance couples, the holiday means more than a fancy dinner and luxury gifts. It's time for reflection and a reaffirmation of love that keeps them holding onto their belief in the other half.

Stephanie Burrel, a Schwarzman Scholar at Tsinghua University in Beijing, and her boyfriend are going into their seventh year together. The two met at Oxford University, where they both studied biology, and the boyfriend moved to California after graduation.

"It is hard being in a long-distance relationship on Valentine's as you often can't be physically with your partner," said Burrel. "But it is still important to celebrate the things that make your relationship special and remember why you are overcoming the difficulties of a long-distance relationship."

This year, Burrel and her boyfriend are planning to Skype for hours, and Liu and Guo, who started another long-distance relationship as Liu moved to Hong Kong for work and Guo stayed in Beijing, will watch another movie or The Big Bang Theory together.