Go with your gut. You DON'T need to move out, and you CERTAINLY don't need to give her your blessing for dating other people while you're still married. She seems to be fishing for space, and for permission to do that, like she already has someone in mind. Just tell her that you think it's disrespectful, and that YOU have no intention of doing so, as it would be breaking your marriage vows.
If she's the one who wants the "space," you should let HER leave. You're wanting to work on your marriage, and keep your family intact, and by her own admission things are peaceful. Why break that stability up for your kids?
Something doesn't smell right to me. Who's this "friend of ours" that she's planning on going to the concert with???
