Warning! SPOILERS for Young Sheldon season 5, episode 12.
The cliffhanger ending about George (Lance Barber) seeking Brenda (Melissa Peterman) to start an affair was secretly answered in Young Sheldon's Mary (Zoe Perry) smoking with Youth Pastor Rob (Dan Byrd). However, it was still able to provide an answer on whether or not he finally slept with Brenda.
George's cheating scandal has been one of the trickiest plotlines for Young Sheldon to tackle. This was first revealed on The Big Bang Theory when Sheldon (Jim Parsons) told Penny (Kaley Cuoco) that he caught his dad having sexual relations with another woman when he was 13 years old. Since its prequel series was greenlit, fans of the original show have been wondering how it will address the storyline. The fact that Young Sheldon features a significantly different George makes this whole thing more complicated. Given the story's pacing, it doesn't have a choice but to at least lay the groundwork for this dark storyline.
Young Sheldon season 5 has effectively floated the idea that George's cheating will begin with an affair with Brenda. After their flirtatious encounter at the local bar, the pair quickly realized that they're mutually attracted to each other. Since then, they've been desperately trying to keep it a secret. Many presumed that after George caught Mary having a smoke and laughing with Youth Pastor Rob, he would've finally acted on his feelings and sought Brenda, but Young Sheldon season 5, episode 12 subtly revealed that it wasn't the case. During Mary's brief stint selling Mary Kay products, she attempted to convince Brenda to get a box from her, and if she did, a tube of concealer would be included for free. Brenda then panicky asked if it's obvious that she's been crying a lot. The fact that she's still miserable and sad implies that nothing has happened between her and George.
It's uncertain how long Young Sheldon will stretch out George and Brenda's back-and-forth flirtations, and whether or not they will even actually start an affair. It's worth noting that Sheldon didn't catch his dad cheating until he was 13, and in The Big Bang Theory prequel, he's just around 11 or 12, meaning the show still has time before it's imperative for them to show George's cheating. For what it's worth, it appears as if they're currently making him more sympathetic to viewers, perhaps in an effort to lessen the backlash on George once he finally becomes the bad father as Sheldon and Mary (Laurie Metcalf) ed him on The Big Bang Theory. The Cooper patriarch has been a good - if not great - family man for the most part throughout Young Sheldon, and the sitcom would quickly become dark and depressing if it immediately shows him being unfaithful.
In any case, Young Sheldon will run until at least season 7. This gives CBS plenty of time to gradually set up George's downfall. In the meantime, Young Sheldon maintains his image as a good dad, albeit with a bit of a wandering eye.
Young Sheldon season 5 airs every Thursday on CBS.