Hello, I'd like to help you with your question.
Even though you were able to do well emotionally the first time you separated after 25 years, you might have had more time to reflect after your divorce how much you missed your partner. Trying to work your relationship out brings on a sense of hope, which no matter the situation can cause someone to feel good. Ending that sense of hope can bring you down, harder than you expected.
When you got a divorce the first time around, it could be that you felt overwhelmed by the bad things in your marriage. And the negatives might have outweighed the positives of the relationship so getting out might have been appealing. You may have not mourned the loss as much because of the circumstances.
When you agree to try to work on your relationship again, you gave yourself something to work towards. There is not only hope but a focus in your life. And that adds
to your life. When your partner decided to leave after one month of trying, that took away your chance to see thing turn out differently and it caused you to lose the potential of a new and improved relationship.
In order to cope, you may need to take a step back and reassess what you feel from what occurred. And try recalling what made you break up in the first place. It can help put the current break up into perspective. It also helps to remember that relationships where at least one person has BPD tend to be more intense and therefore highly exciting and engaging. It may take longer to deal with the loss of all the intensity.
Also, to deal with any pain you feel this time, you may want to write out your feelings in the form of a letter to your ex. Not to send, but to keep and add to as you need to. When you feel you are finished, either keep the letter or dispose of it in a way that makes you feel better.
Work through self help to heal. Learning more about grieving, relationship loss and how to move on can help a lot. Here are some resources to help you get started:
I hope this has helped you,