The proper response is to tell her "let me think about this" and then spend the next week retaining a divorce attorney, taking steps to protect your assets and yourself, documenting everything, making copies of important papers, changing passwords on accounts, making living arrangements, and then filing for divorce.
Serve her the papers and tell her "you're free to do whatever you want with anybody you want."
A colleague of mine had a woman (his eventual ex-wife) served divorce papers while she was in jail for having made false police reports about him.
I had divorce papers served on behalf of a client, on the eventual ex-wife, while she was locked down on an inpatient psych ward.
You don't always get that level of optimal timing for serving the papers, but do what you can.
It is a hell of a lot easier to start a process from a position of advantage and get temporary orders for possession of real property, control of accounts, and interim parenting time or custody of children when you're cleancut and free and the other person is a mess and in jail or in a psych ward.