Are you struggling with some parts of your own life or do you really want something he has.
If I am feeling frustration, jealousy or resentment over some part of my ex's life it always has something to do with an unrecognized or unmet need of my own. I know this because I would not trade places with my ex for all the tea in China. There is nothing about being him I want. When I think of it like that my resentments turn to compassion or at least just observation.
It has gotten easier with time and practice and the destructive feelings almost never make an appearance anymore and what a releif. It is another level of freedom from alcoholism.