Why Does Calpurnia Want To Stay

In this speech that Calpurnia gives to caesar she is very clear she doesn't want him to leave. She makes the claim that since there is bad things she's heard today and that that means that there is likely something bad that's going to happen to him. She uses claim of policy to try to persuade him to stay in. By bringing up the fact that the watchmen had seen such horrifying things she was able to make him feel nervous, she was very careful in her description to prey upon things that would definitely dissuade him from wanting to leave.
Calpurnia is making the assumption that caesar does value his life and doesn't want to die. She is under the assumption that as his wife she will listen to him if she uses enough persuasion. She also assumes