Her lack of response does not mean no. YOu can't assume that. If it is a no, let her verbalize it to you and explain why so you have a chance to make your rationale as well.
The statement about bringing the affair up.....just so ya know, part of that is probably true on her point. If she is trying to move past it and open her heart to you, she can't be reminded of it/him over and over. Yet, you need these pieces first...you need to tell her that. You can let the past be the past once some issues are talked about, etc.
Why do you need to know about the move to have the heart to heart? Is it because you want something to whip out when/if she won't do what you ask her?