Bristol Palin's Ex Calls Her a 'Compulsive Liar' During Nasty Fight During 'Teen Mom OG' Finale

Bristol Palin's baby daddy drama has been fueling her first season on "Teen Mom OG" and the storyline went out with a bang on Monday night's big finale.

The reality star and ex-husband Dakota Meyer have been on the outs since splitting, trash talking each other on social media and in their respective confessionals all season long. Last week, they agreed to meet so they could finally hash things out in person and, hopefully, find a way to coparent in a civil manner.

Let's just say that didn't happen.

Before sitting down together, Palin went to a PTSD therapist to talk about some of Meyer's behavior. Her hope was to find out how to avoid "triggering" Dakota. During their discussion, Bristol explained that she started seeing warning signs before they got married, so she got "cold feet" and called off their wedding. According to her, they didn't speak until their child was born, before they eventually got back together and did say "I do."

"He constantly thought I was going to leave him," Bristol explained, as the therapist said abandonment issues are common with those suffering from PTSD. "Right after we got married he always wanted to beat me to it by thinking I'm going to leave him," added Bristol, "so he'd move out, constantly."

The therapist said they should try to stop making disparaging remarks about each other going forward and told Bristol to avoid knowingly pushing his buttons.

It was then time for the meeting and Dakota came in hot.

"My biggest concern is doing what's best for the girls and not just sticking it to each other," Bristol told her ex. "I need advice on how not to bug you and how to communicate better with you."

"The best way for you to communicate with me is not talk about me, not bring me up, not put me in your social media," he replied. "I don't need you to understand me, you should have tried that when we were married. Honestly Bristol, everything that I've done has been in response to you. I just want you to leave me alone. Go be happy. I'm glad you're happy now. Since you've been gone, ask me how many anxiety attacks I've had, zero."

"It makes me happy to hear that," Bristol said, in a way that did not seem like she was actually happy at all. When Dakota then said he really didn't want any communication with her unless it had to do with their daughters, Bristol started getting fired up.

"Don't flatter yourself thinking that I want to talk to you," she shot back. "We have to get along and the fact that you've got this smirk on your face -- I can see it in your eyes just like I've always seen it in your eyes -- that's why I couldn't stay in the marriage any longer because of this."

He then asked what she would consider a "successful" relationship between the two going forward. "A coparent that doesn't talk to me this way, Dakota," she replied, clearly frustrated. "A coparent that doesn't steal from me. You've got major issues that have nothing to do with me. I think you've had these issues since before we were married and I think you need to work on yourself Dakota, just like I'm working on myself."

The fight had clearly escalated beyond the point of no return, as Dakota told her, "There's one of us on this show who's being real and one of us who's acting. We can have a better relationship for our daughters when you stop being a compulsive liar."

With that, Palin walked away.

"I'm done with this conversation," she said as she left in a huff. "You're a piece of work. I'm not dealing with it."

It should be interesting to see these two come face-to-face again during the reunion. "Teen Mom OG" airs Mondays on MTV.