'Bachelor in Paradise' Goes From Single Guy to Stepdaddy, Another Couple Engaged!!

They're dropping like flies on "Bachelor in Paradise" -- Amanda Stanton and Josh Murray just couldn't resist blowing their secret and going public as a family ... cause they're getting married!

This is where we should probably say spoiler alert, but what the hell -- sources close to the couple tell us Josh ends up popping the question, and Amanda says yes. Only one episode of 'BiP' has aired this season -- and all participants are supposed to lay low ... so they don't ruin story lines.

We're told Josh and Amanda wanted to stay undercover until the finale, but just couldn't stay holed up because her 2 kiddos were getting anxious -- so they hit up the Orange County Fair Thursday night.

Josh is living with them in the OC, but our sources tell us they plan to buy a place in Atlanta.

We broke the story ... another 'BiP' couple, Lace and Grant, were spotted hanging out the day before the show even premiered.