I think you need to get a bit deeper on what makes her feel peaceful. It can take some time to transition to feeling relaxed, and half an hour here or there may simply not be enough time to let her mind stop worrying about the kids and things that need to be done. However, this is a symptom of the problem and not the cause of it.
The cause is more deeply rooted: Why does she feel such a need to remain in control? What does she think will happen if things are not done her way?
Your situation is one that marriage counseling can be very successful in resolving. If you can't/won't see a therapist, try to delve into this topic by asking "Why is *this* important to you?" until you get to the core issues.
Example:
"Why is it important that the meal be cooked your way?"
"Because I don't like how many dishes you dirty when you cook."
"Why is it important to not have dirty dishes when I cook?"
"Because I have to spend time to clean up after you."
"Certainly it's my responsibility to clean up when I cook, but it makes me wonder why is it important to not spend extra time cleaning up after me?"
"Because I take up too much time for everyone else already."
"So it's important for you to have time to yourself?"
"Yes."
"What is it about that that's important to you?"
"Because if I don't get time for myself, I feel like nobody cares about my needs."
"So you feel like I don't care about your needs when I don't do things the way you like them to be done?"
"Yes, sometimes."
"What can I do to let you get time for yourself and show that I care about your needs?"
and so on
The cause is more deeply rooted: Why does she feel such a need to remain in control? What does she think will happen if things are not done her way?
Your situation is one that marriage counseling can be very successful in resolving. If you can't/won't see a therapist, try to delve into this topic by asking "Why is *this* important to you?" until you get to the core issues.
Example:
"Why is it important that the meal be cooked your way?"
"Because I don't like how many dishes you dirty when you cook."
"Why is it important to not have dirty dishes when I cook?"
"Because I have to spend time to clean up after you."
"Certainly it's my responsibility to clean up when I cook, but it makes me wonder why is it important to not spend extra time cleaning up after me?"
"Because I take up too much time for everyone else already."
"So it's important for you to have time to yourself?"
"Yes."
"What is it about that that's important to you?"
"Because if I don't get time for myself, I feel like nobody cares about my needs."
"So you feel like I don't care about your needs when I don't do things the way you like them to be done?"
"Yes, sometimes."
"What can I do to let you get time for yourself and show that I care about your needs?"
and so on
