Q: If a man keeps bad faith for his sister in law although, he did not practically commit anything, but shows his interest in her verbally while communicating with her. Does this effect his nikaah in anyway?
A: This is a totally indecent act. He must stop this immediately. It does not mean that if his nikaah does not break then he must indulge in this type of illicit behaviour.
And Allah Ta’ala (الله تعالى) knows best.