On Monday's episode of "Teen Mom OG" Episode 3, "Old Wounds," Maci Bookout and her ex-boyfriend, Ryan Edwards, discussed parenting Bentley. Meanwhile, Catelynn Lowell confronted Tyler Baltierra about posting photos of their daughter Carly online, and Amber Portwood promoted her book, "Never Too Late."

In the episode, Portwood prepared to leave for her book tour along with fellow Teen Mom Kaitlyn Lowry, who was also promoting her book. She called Gary Shirley to ask if daughter Leah could sleep over. He said no, because Leah had a strict bedtime schedule for school. Portwood decided to take Leah to the park instead. Shirley said he wanted Leah home by 7:30 p.m.

Shirley blew up Portwood's phone as the time to return Leah grew near, which upset Portwood. She dropped Leah off on time.

While on the book tour, Portwood was interviewed on Dr. Drew's radio show, "Love Line." She said that if communication and co-parenting does not improve with Shirley, she is going to fight for custody.

The drama between Portwood and Shirley continues in "Teen Mom OG" Episode 4, "Big News," when Shirley arrives at Portwood's home to drop off Leah. Portwood welcomes him inside. Shirley sits in the living room as Portwood and Leah cuddle on the couch.

Shirley announces that he wants to tell Portwood something before she hears it from Leah.

Viewers can feel the tension building between Portwood and Shirley.

"Are you and Kristina getting married or something?" Portwood asks.

"No, not for a while, if ever," Shirley says, and quickly adds, "I am having a baby."

The expression on Portwood's face is utter shock.

"Kristina is pregnant and before Leah said anything I wanted to tell you," he reiterates.

"Oh, my God," Portwood exclaims.

Shirley attempts to lighten the news by pointing out that Leah will have a little brother or sister.

"Oh, Jesus. Have fun with that." Stunned, it is all Portwood can say.

Portwood tells Shirley that it is weird for him to say he is having a baby with Kristina, but they have no plans to marry, "if ever." She reminds him that he's supposed to get married and then have children.

He reminds her that a person does not have to be married to have a baby.

"You have to think of her feelings when you say things like that," Portwood says, annoyed with her ex. "This is on national television. If you say you're never getting married, but tell me she's pregnant, where's your head at?"

"It's right here," Shirley says and gestures out of view. Portwood scoffs.

Shirley recalls that Leah did not keep them together.

"That closes that door so good," Portwood quips.

"You took the news rather well. I'm proud of you," Shirley says.

If you missed what happened on Episode 3 "Old Wounds," read the complete recap here.

Watch "Teen Mom OG" Episode 4, "Big News," Monday at 10 p.m. on MTV.