Sunday's episode of The Real Housewives of Atlanta was an emotional one for star Porsha Williams. She broke down in tears after learning that Dennis McKinley — her estranged fiancé and father of her 7-month-old daughter, Pilar Jhena — had cheated on her during her pregnancy.

McKinley had admitted to the affair during a therapy session.

"After I heard what I needed to hear, I got up and stormed out," Williams recalled. "At that point, I didn't want to hear anymore. Because for me, I had just heard my fiancé say that he actually had sex with someone while I was carrying our child."

"I didn't want to hear anything else," she said. "There was nothing else I needed to hear, nothing I needed to say. I didn't need to know the reasons, I didn't need to know anything else."

RELATED: RHOA's Porsha Williams and Dennis McKinley Split 3 Months After Welcoming Baby Pilar: Report

RHOA: Porsha Williams 'Beyond Hurt' as Dennis McKinley Admits to Cheating During Her Pregnancy_1
Porsha Williams and Dennis McKinleyCharles Sykes/Bravo/NBCU Photo Bank via Getty

Rumors had been floating around the tabloids that McKinley had been unfaithful, though this was the first time his affair was confirmed to Williams. 

His confession left Williams at a crossroads, unsure of what she wanted to do about their relationship.

Up until that point, the two had been estranged for three weeks, with McKinley asking for his engagement ring back and moving out of the house they shared amid "vicious" fights.

Things got more complicated when the two seemed reconcile, sleeping together after a night watching movies.

That was before McKinely admitted to cheating. Now, on one hand, Williams said she wanted to try to make things work for her family. But on the other, she said McKinely's deceit made it impossible for her to trust him.

"To be disrespected at the most sacred time in life is like, I just can't forgive that," Williams said, in tears. "I'm looking at my daughter, telling her, 'I'm going to work it out, I'm going to work it out.' But some stuff is not forgivable, and I don't think she would want me to have to deal with certain things. I don't think she's want that."

"I'm done," she added. "This isn't anything I'm even capable of forgiving."

RHOA: Porsha Williams 'Beyond Hurt' as Dennis McKinley Admits to Cheating During Her Pregnancy_2
Porsha Williams and Dennis McKinley@stanlophotography

After dating for a year, the two got engaged last September — just two months after Williams learned she was pregnant with their child.

Both appeared to be head-over-heels in love, their romance documented last season on RHOA and on their spin-off special, The Real Housewives of Atlanta: Porsha's Having a Baby.

"I literally wish I could wake up and somebody could be like, 'It was a dream, it didn't happen,' " Williams said on Sunday's episode. "The movie keeps playing in my head. I keep playing all of these moments. We're like creating a real family and just to think it wasn't real, is really hurtful."

"I'm beyond hurt," said Williams. "When I think about my pregnancy, I think about how he was right there by my side. And it makes me think, 'So you were by my side doing what? Planning to go somewhere else?' "

RHOA: Porsha Williams 'Beyond Hurt' as Dennis McKinley Admits to Cheating During Her Pregnancy_3
Porsha Williams and Dennis McKinleyTonya Reeves

RELATED: Porsha Williams Slams 'Snapback Culture' as She Is Being Body-Shamed 4 Months After Giving Birth

Ultimately, Williams said felt what McKinley did was "very unforgivable."

"I am not going to sit up here and take that. I don't deserve that," she said on RHOA.

"The love I had for him. The love that we were building? I would have never betrayed him," Williams insisted. "He could have gotten sick and penis could have not even been working no more, and I would have never betrayed him."

She shared: "I loved him and no one will understand it. As closed up as I was when we I met him, for me to blossom and open completely up to him is how hurt I am."

RHOA: Porsha Williams 'Beyond Hurt' as Dennis McKinley Admits to Cheating During Her Pregnancy_4
Porsha Williams and her daughter, PJAndrew Goldstein Photography

RELATED: RHOA's Porsha Williams Receives Birthday Tribute from Dennis McKinley After Reported Split

Back in June, rumors of Williams and McKinley's split made headlines — two months after Williams had unfollowed McKinley on Instagram.

McKinley denied the cheating allegations in an statement to E! News at the time, saying, “These false and slanderous allegations against me are made solely to damage my reputation, jeopardize my ongoing businesses, and negatively impact my family."

Days later, McKinley shared a sweet birthday message for Williams on Instagram.

As of now, it appears the two have reconciled.

The couple frequently appear together on Instagram, Williams captioning a romantic selfie of the two "Love you Baby" just four weeks ago.

She hashtagged the post, "#Fiance #TheMckinleys #Family #ThickNThin"

The Real Housewives of Atlanta airs Sundays (8 p.m. ET) on Bravo.