It's the beginning of the end for Teen Mom's Catelynn Lowell, Farrah Abraham, Maci Bookout and Amber Portwood on MTV.

With just two episodes left until the girls' series finale, only Us Weekly has an exclusive look at the dramatic moments that'll make for must-see TV, wrapping up some of the franchise's most buzzed-about storylines documented over the last four seasons.

As Bookout plans her son Bentley's 3rd birthday -- with opposition from her ex, Bentley's dad, Ryan Edwards -- Portwood and Abraham experience separation anxiety being away from their tots Leah and Sophia, both 3.

But the end of the series takes an especially emotional turn for Lowell, who placed her daughter for adoption three years ago.

On the final two episodes, Lowell, 20, continues to comfort her fiance, Tyler Baltierra, as he deals with the fallout of his dad Butch's epic fight with his wife, April, who is Lowell's mother. In a scene above, Baltierra gets especially emotional when recalling his decision to give his and Lowell's daughter, Carly, up for adoption.

VIDEO: All about Catelynn & Tyler's upcoming wedding

"I would lie to you if I said I didn't regret it sometimes," Baltierra, 20, admits in the teaser clip above. "I was literally petrified about being the sh---y dad that my dad was."

For much more of what to expect from Lowell, Abraham, Bookout and Portwood's final two episodes of Teen Mom, watch the clip above now and tune in August 21 and August 28 at 10 p.m. (EST) on MTV.

This article originally appeared on Teen Mom's Tyler Baltierra: I Sometimes "Regret" Giving Carly, 3, Up for Adoption