comma before 'so' [conjunction]: he was cheating on me so I told his

[Rabelaisian]

Normally, I always put a comma before "so" when it means "hence" or "therefore" or starts off an independent clause, but what if I don't hear the pause there in the line of the character's dialogue? Is it okay to omit it? For example:

“I thought he was cheating on me with my sister so I told his friends.”

Thanks.

Source: me.

 

[Beryl from Northallerton]

If you want the actors to understand what you've written, then I'd suggest using commas where necessary.

 

[Rabelaisian]

Actors? No, it's not a script; it's novel writing. Are you saying that it's hard to understand that sentence without a comma before "so"?

 

[Beryl from Northallerton]

I'm saying that whoever ultimately reads your work will primarily need to understand it. If the reader becomes confused, then that will detract from their enjoyment - an undesirable outcome.
I don't think that your sentence, taken on its own, causes much pain, comma-less, but if I kept on snagging on what I might consider to be slightly ambiguous exchanges, that would take me out of the story.