Give it a week or so, but don't wait too long. You could always say that you have some things that you are working out and would like her help to get you through some things. Flip it around so it sounds like you are the one who is getting help.
Her having the fling with another woman is a big flag that she needs to get through her issues. Sweeping them under the rug isn't fair to you. In fact, if she is unwilling to go in because it's something that's important to you, then she's not all in to the piecing.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.