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After nearly a year and a half of dating, "Teen Mom' star Maci Bookout was ready to walk down the aisle with boyfriend Kyle King, but her man clearly had different plans.

PHOTOS: Inside Maci's relationship with Kyle

The new issue of Us Weekly reports that Bookout's constant pressure to get hitched pushed King, 23, away and that the couple called it quits in early February, just days shy of their two-year anniversary.

PHOTOS: Adorable pics of Maci and Kyle with Bentley

"Maci wanted something way more serious," explains an insider of Bookout, 20, who had been living together with her childhood pal since the summer of 2010. "She was never happy enough just being a couple. She always wanted more, more, more, whether it was a ring or another baby."

King wasn't able to handle the pressure and "broke it off," says the source. "It's really sad because they love each other, but she pushed him away."

PHOTOS: Sad celeb splits

For much more on the couple's shocking split -- and details on how Bookout's son Bentley is coping -- pick up the new issue of Us Weekly, out Friday.