Honestly the real question is why WOULD he tell Chase anything? He’s not planning on staying with Chase yet, he’s still planning on breaking it off once they’re done guarding him. What he going to do, say, “oh btw you marked me and I had your baby. Bye!” ???
We’re either going to need Josh to get emotionally invested and not just all YES I MUST FUCK THE FACE or something forces him to come clean and then it’s easier for him to be emotionally invested because now he isn’t hiding secrets.
So far I am leaning towards the second option. I think either they do split, and then a sad broken puppy shows up at Josh’s door, which will both force Josh to fess up and pull the heart strings, or something forces him to come clean before his contract is done.

The plot needs to start plotting bc like why hasn’t he told chase anything yet ????