Focus on yourself and set goals to make yourself happy and elevate your life. I haven’t found anyway to deal with a hard breakup in the past, I think you’ll always remember your ex or think of them from time to time, but it is possible to move on, it just takes time. Put yourself out there, meet new people, date, etc. the fact remains that you’re no longer together … if it was something they did (like cheat) then be thankful they showed who they are and think about how you deserve better, if it’s your fault, work in where you went wrong so you don’t repeat the same mistake with the next one. If it’s mutual and there are no hard feelings, then maintain a friendship to see if you can eventually rekindle that relationship, or maybe just stay friends moving forward.
Most of the time when people break up it’s because they weren’t meant to be, it’s hard to believe that when you are the one dumped and still have feelings for that person, but any time spent with someone who doesn’t want you 100% is time wasted that could’ve been spent with someone who does want you, or at very least time that you could be spending building your life to exactly who you want to be.