Biggest mistake of his life

My husband and I separated last April, we have been hanging on by a thread. Honestly the only thing keeping us together is our sex life.

Well after hard convos and many this is it we’re divorcing times we decided to work things out… after a couple weeks he starts getting very cold with me and tells me when his son graduates I don’t want to stay in this state. I said I cannot leave I have kids and own a business. I told him if he doesn’t want to stay in this state I’m done. I am not doing this anymore. So he tells me after I end it that I’m the biggest mistake of his life.

How would you react to this? Any advice? My heart is crushed