As Belinda watched her husband

[Bassim]

I am wondering if my sentences are grammatically correct.

As Belinda watched her husband reading his newspaper and sipping his coffee, a thought stirred her mind that he was hiding something from her. Her intuition warned her that behind his calmness a storm was raging.

 

[teechar]

I would use "read" and "sip" (instead of "reading" and "sipping) in the above.
I would also say "stirred in her mind."
Finally, I would add a comma after "calmness."

 

[Lynxear]

I have no problems with the use of "reading" or "sipping" in your sentence.

I do agree with "a thought stirred in her mind" and the comma after "calmness".