Josh isn't the dog??? these two things happened on separate occasions. The one with Grayson telling Chase he slept with a dog happened one of the first times Chase went into rut. Chase sleeping with Josh (although he can't remember it) happened when Josh was working as his bodyguard around 5 years prior to the current events. Chase went into rut and josh got pregnant but josh isn't the dog, these 2 events are from 2 different times in the story.
Chase just looked at Josh, who apologized with a faintly trembling voice. Josh braced himself for any criticism Chase might have, thinking he deserved it. He prepared for this moment, knowing it could end everything. He was ready to go back to the way things were.
As a sharp pain stabbed his heart, Chase suddenly murmured,
"...I'm relieved."
Josh blinked in surprise. Incredibly, Chase's eyes were filled with tears. He meant it. Chase let out a trembling sigh and spoke.
"I knew I slept with someone."
"..."
"There was definitely someone who triggered my rut, but I couldn't remember anything. I've been searching for years..."
"You've been looking? For me?"
"Yes."
When Josh asked in surprise, Chase covered his face with his hands and let out a shaky breath.
"I couldn't find anyone or any traces, so I started thinking maybe I really did it with a dog."
"No!"
Josh hastily interrupted.
"You didn't do it with a dog, Chase."
Chase visibly stiffened. Josh continued, unable to hide his pity.
"Grayson lied."
Slowly, Chase lowered his hands. His face showed his shock. Josh gently kissed his forehead.
"You kept refusing him, so he lied to scare you..."

It's near ending so I decided to just read the novel and whoever lied to me saying that Josh is not the "dog", I hope your pillows are warm on both side on summer and wet on winter. Josh is actually the "dog". Chase knew he went into rut with and had sex with someone but doesn't know who and that fcking stupid jerk of his brother told him maybe it's actually a dog and traumatized Chase to the core. But yeah, it's near end and I think like 10 chap??? Unless the artist/author decided to make the bonding between chase and pete more in depth(????) idk. A good read tho.