It's completely understandable and somewhat expected for people to be unhappy about getting a divorce. None of us gets married and expects to get divorced. Divorce can be costly, frustrating, hard on your kids, and even volatile. Why would anyone even consider being happy about the situation?
Yet, what really are the alternatives? Staying miserable for the rest of your life? Blaming your ex for all of your unhappiness? Hanging on to resentment and regrets? Do you really want to spend the rest of your life in that kind of misery?
So how does one have a happy (or at least happier) divorce?
1) Regardless of who left whom, take it as a step in the right direction. If you left him, you must have had a good reason and for that you should know that you are moving forward. If he left you, even if you are grieving the loss, know that having him stay wouldn't inevitably make either of you happy. Do you really want to be with someone who doesn't want to be with you? Don't you deserve better than that? Holding on to your ex or the past will only hurt you and keep you from enjoying a life well lived. Resentment is understandable but it isn’t at all helpful. If you are having trouble letting go of the anger and resentment, get some professional help.
2) Fake it until you make it. Act happy; look for positive things to look forward to or to enjoy in the moment. Walk away from negative people and negative situations. Don't ruminate or obsess about what could have been, what good is that? Don't incessantly tell others how awful your ex is or how miserable you are. Instead have faith that everything will be all right, tell yourself so frequently, and start to do things that bring joy into your life not hurt. This is your opportunity to find out what makes you happy not just how you can make others happy. This will be one of the most important skills of your life.
3) Change your story. "I don't deserve happiness." "I always pick the worst partners." "I'm not pretty enough to meet someone wonderful." "I'm too old to find someone new." These stories find their way into your psyche and literally beat the crap out of you. Is this what you want? Do you want a miserable, hopeless story to live out for the rest of your life or are you ready to rewrite that old, useless story? Convince yourself to tell people a new story, write it, repeat it, and own it so that you clear that old nasty one away. A new story might be, "I am enough." "I am loveable." "My life is filled with love, kindness, and joy."
That old story is negative programming in your brain and the only way to change it is to reprogram. Yes, you won't believe the new story at first. That's ok, keep saying it, start to own it and it will become yours. If the story you tell yourself is a miserable one, it will be the one you live. If it's a positive, hopeful one, then that is what you will start to attract in your life.
Here's the bottom line, you have two choices; get divorced and be absolutely miserable or get divorced and work toward happiness. You have the choice regardless of what's going on around you. If your soon to be ex is making the divorce difficult or volatile, you don't have to react to that. Control what you can, let the rest go and know that soon all will be better. Holding on to what might have been won't help you or anyone around you. It is possible to have a happy divorce; it just takes a little bit of work.