Complex sentence: Nene discovers that she is pregnant with Gabby's baby, and she gladly tells this to him; but to Nene's dismay, upon hearing of the said news, Gabby instantly yells at her with disbelief.
Split into simpler sentences: Nene discovers that she is pregnant with Gabby's baby, and she gladly tells this to him. To Nene's dismay, upon hearing of the news, Gabby instantly yells at her with disbelief.