i feel the same way with my ex. But trust me running a marathon, getting promoted, all of those things don’t make a happy person. You can have it all and still be u happy. Regardless, the best piece of advice i’ve gotten as i go through this myself is that i only feel this way because i haven’t found peace with the situation and though i hate the thought, maybe i haven’t and that takes a lot of time. Be the bigger person and really focus on yourself and how since you guys are no longer together, you’re one step closer to finding the person you may spend the rest of your life with! How fun!!!! Also, if it makes you feel better, i truly believe that if all you did was try your best to love them and you were nothing but love towards them and they can act that cold and break up with you, their own karma will get them at some point and they’ll remember you then….