Realizing and understand your mistakes is the first step to healing from something deep. All the blame is not on one person; you share that blame just as much as you share a bed. Mentally you have to understand your faults and false dreams as well as you heart. the two are completely different. In order to have no hard feelings towards each other you have to respect how it made the other feel at the moment or continuously. Understand that you are not always right and it is okay to try new things to make something work. Realize that your approach to everything may not have been the right approach and you could have handled it differently. 

Instead of thinking about it in a selfish more vengeful way to make yourself feel better, be more realistic to reality. Nobody is perfect, everyone has flaws, no matter how much they do to hide them. Living life and being happy with life is not only financial. Money brings several things, but pure happiness is not one of those things, it's called being content and satisfied. Everyone needs someone but that someone will not be easy to hold onto. Making sure you know your own faults will help you be more successful at finding what you want in life and who you want to share it with. 

Know your worth and what you will do to live up to it. Never dull your light for someone else to shine. Always polish your own glow before doing anything else. Accept or change your flaws and make the best out of what life has to offer.