I agree with the others. I see nothing in her message that jumps out at me and screams “I am trying to leave you for another man.” Nothing at all. OTOH, you COULD read it that way if you really wanted to, in fact you could read it lot of different ways.
One thing that I did see is that she is confused about what you want and why you are so anxious. She is trying to figure YOU out and I think that if she can see where you stand, she will be able to determine where she stands.
Look at this from her POV. For years you have been shut down to her. As she starts on a new career and begins to feel independent and good about herself, you start pushing to improve the M. What gives? Assume for a moment that she is really NOT having an affair (as incredulous as that may seem to some people), but rather searching for direction on her career. She may not have paid much attention to your questions about whether she is having an affair, so your anxiety may not make any sense to her at all.
You might think about telling her at some point exactly what you are seeing and what you are concerned about, that you suspect she is having an affair and that you are worried. That might turn on the light bulb in her head to understand where you are coming from and let her know what she can do to show the effort you are looking for.
