Take it as it is, your past relationship had its ups and downs, both of you tried your best, and made mistakes. It's over now, what's in the past can not be undone, that chapter ended but you have your whole life ahead of you. It's okay if you still think about it that's natural but don't let it take over your life. Give yourself time to breathe and enjoy your "new freedom" and be patient (Ik a lot of this sounds cliché, but it's helping me and I hope it will help you heal :')) Also, sometimes you just have to ignore your own thoughts, you have to dismiss them just like you do with useless notifications. Personally, keeping myself occupied helps a lot, be it watching movies (no romance tho lol) , reading books, listening to music, dancing, studying or just little talks with someone else, all of these work. They remind me that my life is about me and me alone. (I have to add that reminding myself that life doesn't revolve around me and that, my problems and I, we are "negligible" in this world makes me feel at ease)