How do I fill up all the time I used to spend speaking to him or texting him?
At the risk of sounding like a broken record- Alanon? Counseling? You said you didn't have time for those things before. Maybe you do now.
Agree with all the previous posters. Take care of you. You'll never look back and regret time you spent taking care of yourself, whether it's writing in a journal, taking a hot bath or keeping in touch with friends who care about you.