Found online Psychology Today:
4 Reasons to Stay Out of Contact With Your Ex
You can't keep bouncing between fantasy and disappointment.
The sting of a breakup or divorce is painful and disorienting. Adrenaline courses through the body and the mind races. The suffering party thinks, “This can’t be happening.” And with that thought paramount, the individual seeks corrective action—talking it out with the ex, identifying the fix that will save the relationship, or in some way buying time through compromise, temporizing, papering over: Whatever it takes.
And yet the single best way to accelerate the healing process after a breakup or divorce is this: Stop contact with the ex.
If you are trying to recover from the end of a relationship, this advice may be difficult to accept. Your mind may already be working overtime to rationalize why it's OK for you to stay in direct contact. You may say that you have to give your ex-partner their stuff back. Or that you think it is best to keep living together, for a while at least. You may say that you have to check in on your ex’s family members. Perhaps there is a birthday coming up, or some other event. And what harm can it do to see what the ex is up to on social media? You assure yourself that you can break up and still stay friends.
In reality, the only legitimate reason for contact not to be avoided is if you have children and must communicate about co-parenting responsibilities—and even in that case, you should maintain boundaries by limiting conversation to matters pertaining to the children. Otherwise, continuing, or attempting to continue, communication with your ex will only prolong your suffering—and prevent you from beginning a productive process of letting go.
Here are four more reasons to stop contact with an ex:
1. You can't heal.
Ending a relationship is difficult, but the painful feelings are not permanent. You will feel sad, you will feel angry, you will feel a sense of shock that your life has taken this turn. As I describe in Breaking Up and Divorce: 5 Steps, these feelings are normal, and they're part of the recovery process. Eventually, if you allow it, a kind of acceptance will come into your life. However, if you persist in contacting or attempting to contact your ex, you are working against the recovery process and in favor of a self-defeating strategy of denial. This may buffer the blow but it cures nothing. It just allows you to put off fully accepting difficult feelings and your new circumstances. Confronting the difficult feelings and accepting the fact that your ex is no longer there means you are now on the path to healing. There is comfort in this and as you persist your world will grow brighter.
2. You can't let new energy in.
Even if you are not consciously aware of it, if you are still in contact with your ex, you are continuing to devote energy over to that relationship, which can no longer be what you need and want. Each time you talk to your ex, work to make contact, or think about when you will next be in contact, you siphon off the energy needed to pursue new life experiences.
3. You live off fantasy.
If your relationship has ended, then it's over: What you had with your ex no longer exists. It will never be the same. Continuing the connection means that a part of you is still hoping that in some alternate universe there is a chance you and your ex can be together and be happy. As a result, you live off moments of closeness. But each time you come in touch, you are reminded that you no longer have your ex and you face crushing disappointment all over again. This roller coaster gets in the way of real life and its actual opportunities for happiness.
4. You relive your mistakes.
Part of what is so hard about managing relationship endings is that the injured party tends to blame himself or herself. In some ways, a relationship ending should be an opportunity for personal growth. However, it is a mistake to remain, or attempt to remain, in contact with an ex in the hope of achieving a chance to do things over.
Like a character in Groundhog Day, you'll wake up with the same fears and upsets about yourself as you did the day before. This is because maintaining contact keeps you stuck in limbo: You can’t be with your ex but you can’t move on. Once you let go—completely—you gain the freedom to live, mostly unencumbered by the regrets and hurts of yesterday.