So what's the big issue about having a cliff hanger in your book?
It's not like life isn't filled with cliff hangers.
Waiting for the results of a medical test.
Waiting 9 months to find out the sex of the baby.
It's not like they don't happen in movies or TV.
Movie - the original Star Wars. The movie ends with the heroes getting their medals, but also Lord Vader's ship spiralling out into space- so he isn't dead and could come back.
Let's try another one - Harry Potter and the Deathly Hallows - part 1. End of the movie - Voldemort opens the tomb of Dumbledore and gets the wand. (should I have said spoiler alert - lol)
TV show - oh - say any show that has a season finale.
Yet - it isn't allowed in books.
Two words - bull and shit. Put them in any order you like.
What Happens in Bangkok is a 3 book Trilogy - so if everything is wrapped up in a neat bow at the end of the book - then why write the next book?
Oh - I could contrive an issue - the main characters have some stupid fight and break up and then I use the whole 2nd book to get them back together again,
Like that's ever been done before.
No- to me a series should flow book 1 to book 2 to book 3.
Am I ever going to use a cliff hanger again - who knows.
I will always write my books the way I - the author - think they should be written.
And yes - I know I have to take the heat.
But it wouldn't be the first time an artist/actor/singer/writer has taken the heat for not bowing to the will of the people and producing their art the way they see fit.