The best revenge is a life well-lived. Being angry is a waste of time. It's like drinking poison and waiting for the other person to die.
How about maybe make a list of all the good things about him being gone. I have found that gratitude, practiced daily, is a great help. And...just because it appears he is living a care-free life, doesn't mean it's true. I'd much rather be the one with a home and a beautiful child who looks up to me and loves me and knows that I love them.