Amber Portwood is finally fighting back after watching her ex-boyfriend, Gary Shirley, and his wife, Kristina Anderson, question the paternity of her second child on Monday night's new episode of the seventh season of "Teen Mom OG." Following the show, Portwood, who is expected to welcome a baby boy [VIDEO] with Andrew Glennon in May, took to Twitter to set the record straight about when her romance with Matt Baier ended and her relationship with Glennon began.

"I think there was a break between [Matt Baier] and Andrew," Kristina Anderson said on Monday's show, according to a report by Cafe Mom on February 14. During the same conversation, Shirley took things one step further and said that he hoped Portwood's baby wasn't Baier's [VIDEO].

When did Amber Portwood's relationship with Matt Baier end?

After watching the events play out on "Teen Mom OG," Portwood shut down the swirling rumors that suggested her second child could have possibly been fathered by her former fiancé. "Me and [Matt Baier] broke up in May." As fans well know, she and Baier called it quits after he failed a filmed lie detector test and failed to make amends when they appeared alongside several other reality stars on "Marriage Boot Camp: Reality Stars Family Edition" in the weeks that followed their breakup.

While filming the WEtv series last summer, Portwood met Glennon and in August 2017, she confirmed their romance with a photo of Glennon holding a rose on her Instagram page. Days later, the couple made their red carpet debut during an appearance at the 2017 MTV Video Music Awards.

Amber Portwood wasted no time getting pregnant

Just one month after becoming Instagram official, Portwood and Glennon traveled to Hawaii and during their trip, as fans saw during a recent episode of "Teen Mom OG," Portwood took a pregnancy test and learned she was expecting baby number two. As the season continued, Portwood was seen telling her family about her pregnancy as her daughter, nine-year-old Leah, got to know her new boyfriend.

Although Amber Portwood and her boyfriend are not yet engaged, they seem to be quite serious about their future and after meeting in Glennon's hometown in Los Angeles, they've moved in together in Indianapolis, Indiana, where Portwood and her family reside.

To see more of Amber Portwood, Andrew Glennon, and their growing family, don't miss "Teen Mom OG" season seven on Mondays at 9 p.m. on MTV.