[Warning: The following contains spoilers for Episode 3 of A Million Little Things! Read at your own risk!]

The secret is out on A Million Little Things and it is has splintered Jon's (Ron Livingston) group of friends even further after his suicide. Now that Gary (James Roday), Rome (Romany Malco), Regina (Christina Moses), Maggie (Allison Miller), Ashley (Christina Ochoa) and Katherine (Grace Park) all know about Eddie (David Giuntoli) and Delilah's (Stephanie Szostak) affair, there's a new cloud hanging over the group.

Gary had the explosive response when he found out that his best friend had the nerve to sleep with their other friend's wife. To be fair, the bomb was dropped on his birthday when the guys were supposed to be celebrating with their dream day at a Bruins training camp. However, it was Eddie's wife Katherine who delivered a tour de force of emotions once she discovered who her husband had been sleeping with for months.

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The first two episodes of A Million Little Things painted Katherine as an over-worked, cold woman who put her job above her family, but her devastation after finding out what her husband had done added an entirely new perspective for the audience on her character. Her quiet confrontation of Delilah in a parked car in front of Delilah and Jon's house is the most heartbreaking scene the show has deployed so far, and this is a heartbreaking show overall.

Showrunner and A Million Little Things creator DJ Nash talked to TV Guide about crafting that scene and the effect this secret will have on the group moving forward — including the few who still haven't felt its devastating ripples.

Grace Park, <em>A Million Little Things</em>Grace Park, A Million Little Things

Was there a version of this episode where you allowed Katherine to just like absolutely lose it on everyone or did she always have this kind of quiet response to the affair, specifically in the car with Delilah?
DJ Nash: I think Grace Park is incredible and I have written a version of this character in a number of things I've done before. Her skills as an actor, the well she's pulling from in her own personal life, and what she's doing, she is such an incredible addition to our show. ... In terms of the restraint she shows, I love Grace's ability to present Katherine as someone who is both strong and vulnerable at the same time.

We don't want to do that thing if it's not authentic and it doesn't ring true, but I think that speech where Katherine basically says to Delilah, "I could yell at you, but you've already paid the ultimate price" is so much more hurtful and damaging than anything else she could possibly say.

I feel like when she was saying those lines that you mentioned, it was like your parents are telling you they're disappointed in you, which is worse than if they just yelled and grounded you.
Nash: Totally, totally, exactly right, because in that moment, at that point of the day, Delilah's already put herself through the ringer. I mean, she already feels horrible about what she may have done. She feels terrible about it. I definitely hope you catch, in the office, her remorse. So when she comes home, when they're in that driveway... these two women are not so different. You're going to see [that] over the course of the series. When you learn the backstory of their friendship, you will realize just how close they were and we'll see them try to rebuild that, as hard as that may be.

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It comes up multiple times in this episode that Gary is much harsher on Eddie than he is on Delilah. Why does it seem that he's able to forgive Delilah a lot more easily than he's able to forgive Eddie for what happened?
Nash: I think the biggest reason for that is that he runs into Eddie closer to finding out the truth. By the time he gets to Delilah, he's had a whole day and [he is] sort of physically exhausted and emotionally exhausted. ... As he says, "Why aren't you yelling at Delilah?" "Because she's not here."

So that's the initial thing. I also think there is this idea of a guy code and about this violation that Eddie has done which, for Gary, sort of the guy's guy, strikes a very deep part of him. So, I think there's a bunch of factors going on there. I also think that there's a part of Gary that has inherently looked out for Delilah. He was the one who was in the driveway with her. He was the one who comforts her at the funeral, so there's a brother/sisterhood there that may inform why his response is different.

Who is going to have the hardest time now that the secret is out?
Nash: I think the people who are going to have the hardest time definitely are Eddie and Delilah because they are the ones to do it. As hard as this is on Katherine, she can take comfort in, "I didn't do that." I think it will hit all of them in different ways and in waves at different time. ... I think, truly, the remorse and regret of Eddie and Delilah, especially in Episode in 5 and 6, will get even worse.

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When are you going to break my heart and have Sophie find out?
Nash: I am not at liberty to say. That is going to be really, really difficult. As Delilah realizes, [Sophie] just lost her dad and she cannot lose her mom. She cannot lose her mom. If Sophie learns the truth, the fear is that Delilah will lose her and it is ever present.

The episode is a big moment for Gary and Maggie as well. What's next for them and what does Gary have to do to get Maggie to see this is more than "fun" for him?
Nash: That is Episode 4. Episode 4 does exactly that.

A Million Little Things continues Wednesdays at 10/9c on ABC.