As the Inspector Said

This is the ending of a story from my student's book, I had to write it for school. Please, tell me what is wrong {and good, too} and what should I correct, it's really important for me.


Sonia was looking at <font style="background-color: rgb(255, 255, 0);">her husband, her heart beating fast</font>, when she realized that her plan hadn’t worked right. She wasn’t able to say anything to Robert, she could only think what could had happened to Charles.
‘Do you know who it was?,’ asked Sonia’s husband, putting his gun on the commode. ‘You know, don’t think I’m blind, you stupid!,’ he shouted at her. Sonia was thrilled but she decided to pretend that she doesn’t know what’s happening. ‘Robert! What are you saying? What do you mean?<font style="background-color: rgb(255, 255, 0);"> Oh, honey, how are you feeling?’</font>
‘You… Don’t pretend to be innocent! I have seen it for months but I never though that you would want to kill me!,’ he shouted and he slapped Sonia. ‘What are you saying? <font style="background-color: rgb(255, 255, 0);">Who is it?</font>’ She curled up on their bed, began to regret what she had done. ‘Your mad lover! We’ll see what the police want to do with you, you’re a… Criminal! My wife! They are going to gossip! I’m the husband of a psycho now!’
‘Robert! Oh, honey, what have you drunk? I will give you some…,’ said Sonia, but Robert was killing her with his gaze. ‘Don’t lie anymore, it doesn't make any sense now, Sonia!,’ the man told his wife. The woman looked at the floor. It’s over, she thought. ‘What have you done with…,’ she asked. She wasn’t able to say Charles’ name. ‘He escaped, I didn’t kill him,’ answered Robert.
"I must go to the toilet," Sonia caught her stomach and began to walk to the door. Robert hid his face in his hands. And then he heard a gun explode behind him. In the moment he felt pain. He turned back and saw Sonia holding his weapon. ‘What have you done…?,’ he said but it was too late to hear the answer. He felt weak and fell down. ‘I’m sorry, Robert. Ain’t my fault you were a bad husband… Sweet dreams.’ She shot him in the head. Everything became dark.