Going by Mobygames dates,
The Windows version of The Room came out 2 years after the iPad version.
The Windows version of The Room 2 came out 3 years after the iPad version.
The Room 3 came out in 2015 on iPad, and according to the Fireproof Games website (the developer website) they hope to start work on a PC version in 2018. http://www.fireproofgames.com/2017/11/the-room-three-pc-update
So don't hold your breath, but there's almost sure to be one eventually. Not soon though, and quite likely not this year.