Complex sentence: Chase calls his ex-girlfriend, Natalia Kowalski, to make sure she is okay, only to find her bitterly unhappy due to Chase accidentally revealing her identity on television during Rex's trial, forcing her to go under witness protection.
Split into simpler sentences: Chase calls his ex-girlfriend, Natalia Kowalski, to make sure she is okay. Natalia on the other hand is bitterly unhappy due to Chase accidentally revealing her identity on television during Rex's trial, forcing her to go under witness protection.