Sometimes you can be the best partner in the world, and they still leave. Sometimes it's not you that caused them to leave; it's who they are. If you know you’ve done everything you could for the relationship and you know you were good to them then let them go as in that case it's you, its just who they are. And you can’t change who they are. People are going to say and do what they want even when they know they have done you wrong and your hurting from the breakup. So don’t live in the past thinking about all the time and energy you put into the relationship. You can’t get the past back after you invest in the relationship.