Jay Z started talking about the infidelity when he addressed the scars he still has from his past.
Those scars led to him push away his wife, 36. And that led to the cheating that she addressed in Lemonade.
"You have to survive. So you go into survival mode, and when you go into survival mode, what happens? You shut down all emotions.
"So, even with women, you gonna shut down emotionally, so you can't connect. ... In my case, like, it's deep. And then all the things happen from there: infidelity," he said.
He has never named the woman he cheated with. Beyonce has called her "Becky with the good hair".
First she touched on his straying on Lemonade.
Then he addressed it on 4:44.
But he said that it was not planned that way and they were actually going to do a joint album.
"We were using our art almost like a therapy session. And we started making music together. And then the music she was making at that time was further along. So, her album came out as opposed to the joint album that we were working on."
He added: "We still have a lot of that music. And this is what it became. There was never a point where it was like, 'I'm making this album'. I was right there the entire time."
The music made them "very, very uncomfortable".
Jay Z told the NYT: "But the best place in the hurricane is in the middle of it.
"The best place is right in the middle of the pain. And that's where we were sitting. And it was uncomfortable. And we had a lot of conversations.
"[I was] really proud of the music she made, and she was really proud of the art I released.
"And, you know, at the end of the day we really have a healthy respect for one another's craft. I think she's amazing."
And Jay Z even hinted that they could have divorced.
"You know, most people walk away, and, like, divorce rate is like 50 percent or something 'cause most people can't see themselves.
"The hardest thing is seeing pain on someone's face that you caused, and then have to deal with yourself.'
Jay also took the time to talk about those scars and how he has faced them with the help of therapy.
"I grew so much from the experience," he said.
"But I think the most important thing I got is that everything is connected. Every emotion is connected and it comes from somewhere. And just being aware of it. Being aware of it in everyday life puts you at such a ... you're at such an advantage. You know, you realize that if someone's racist toward you, it ain't about you.
"It's about their upbringing and what happened to them, and how that led them to this point. You know, most bullies bully. It just happens. 'Oh, you got bullied as a kid so you trying to bully me'. I understand."
This understanding has caused him to soften.
"And once I understand that, instead of reacting to that with anger, I can provide a softer landing and maybe, 'Aw, man, is you O.K.'?," he said.
"I was just saying there was a lot of fights in our neighbourhood that started with, 'What you looking at? Why you looking at me? You looking at me?'
"And then you realize: 'Oh, you think I see you. You're in this space where you're hurting, and you think I see you, so you don't want me to look at you. And you don't want me to see you'.'