In Touch can reveal that Kim Kardashian’s baby announcement has been painfully bittersweet news for the star’s younger sister Khloé Kardashian, 28, who couldn’t help but feel shattered after more than three years of trying to get pregnant.

“Khloé has been telling everyone she’s so happy for Kim — and part of her is — but deep down, she’s heartbroken,” a pal tells the new issue of In Touch, on newsstands now. “She wants a baby so badly and feels like everybody around her is able to have kids but her.”

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Breaking the news to Khloé wasn’t easy for Kim, who has sat alongside her sister at the fertility doctor’s office and knows how desperate she is to be a mom. “Kim told everyone at the family Christmas party [on Dec. 24],” a source close to the Kardashians tells In Touch. “She was scared to tell Khloé — she really didn’t know what to do or how to tell her.”

When Khloé heard the news, there were tears, confirms the source. “She went full force on the champagne at the party,” reveals the pal. While Khloé has done a good job of hiding her pain, insisting to fans that she is “so freaking excited” for Kim, in reality, “Khloé is hurt and jealous,” says the pal.

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When Khloé wed Lamar Odom, she believed in love and marriage, followed by a baby carriage. “She was supposed to have the true romance that neither of her sisters had, settle down and start a family,” the source continues. “It’s really hard for Khloé to see both her [older] sisters having kids…. Neither of them is even married yet.”

For more on Khloé’s baby struggles, pick up this week’s issue of In Touch, on newsstands now!