I'm going to mention a "rule" we speak about here, known as the "48 hour rule".
The rule is about waiting 48 hours before responding to something from our spouses that isn't serious or a crises that needs immediate attention.
What this does is it helps us practice detaching. Meaning, we don't respond to something in the moment as a reaction. Rather, we take a moment to think about it before we respond... IF we respond...
Now mind you, your W opened the door for you to talk "if you need to". So it sounds like an open and honest invitation.
Many of us have been down that road and so we decide we need to talk and start dumping all our stuff at our spouses feet, which often leads to our spouse using that as a way to prove we are wrong, bad, etc and prove they are justified in leaving.
You COULD reply to her thanking her for the offer and that you really need time to be with your thoughts, at this time. That would be all. You are acknowledging that you received her "kind" offer and respectfully declining for now.
