Before, you knew what they're schedule was for the day, what they ate for breakfast, what deep and meaningful thoughts they've had, if any. Now you don't know anything because you're not there anymore, sharing the same space, sleeping in the same bed.
But you also find out that you didn't know the person as well as you thought. The process of breaking up itself teaches you things about your partner--how they deal with loss, how important you are, how hard they'll fight for something they believe in.
To me, the saddest thing of all is how cruel the other person can be in the breaking up process. How they can act like someone who never loved you at all. As though you had never made vows to spend the rest of your lives together. Suddenly they can become a person who despises you and your sadness.
I've had the good fortune of not being broken up with in this way, but I have to admit, I understand why people do it. Personally, I preferred the passive approach. I always had an exit strategy--a guy who conveniently fell in love with me and could help me leave. A guy whose needs I could focus on to drown out the pain of hurting the other person.
It's shameful to admit, and it's so inconsistent with the person I see myself as being, the person that I strive to be. But there it is, example after example of exit strategies in my relationship history.
In my second marriage, I toyed with anger and exit strategies, but in the end I decided that I was going to have to stay in the relationship until I could leave in a respectful way. I had to find a way to be loving to both of us, or I wasn't allowed to leave at all.
I am proud that I did at least honor that commitment. But I can see why people don't leave in this way. It's easier to vilify the person to justify why you've left. Much easier than it is to hurt a good person who didn't do anything to deserve it.
This is the hardest part of the empathy/pick me thing. Because no matter what happens, you're still going to get hurt. To this day, it still makes me cry, even as I write this, knowing that I caused him pain. I think I might even be sadder about it than he is at this point.
The only consolation I can find is that if you at least try to leave in love rather than hate, you minimize whatever pain is in your control.