Do I need his permission to open my first solo 401K?

My tax accountant advised me to open a solo 401K, before the end of the year so I can start saving money towards my retiremtn. I am in the middle of my divorce. Is it OK to just inform my soon to be ex if he has any issues by my opening a solo 401K and then open it. or ask him for his permission that is he ok if I open a solo 401K?

thank you,