I can't help but to think that my marriage will end in a divorce. not a matter of if but a matter of when and I feel numb about it.
Why do you feel like you're going to end up divorcing your partner?
The stars say it will surely end in a divorce and I just live day by day until then.
I'm sorry that you think so, but  believing in the stars is unreasonable and you shouldn't believe that. You're supposed to live and cherish your partner when you're married and you seem to be ruining it for no reason.
Whatever you say, I still don't care much about my marriage.
I think you should care about your marriage as you made a promise to your partner that you will love them and strive to make it last. If you no longer care, try to be more honest with them and file for divorce so that your partner can find their happiness somewhere else who would care for them and cherish them for who they are.