If you have already broken up, then you are still concerned about the details of your predecessor, or you are too affectionate to let go, or you are looking for yourself to suffer.
Any relationship, from the moment you break up, this person has nothing to do with you. Even if you used to be close lovers, this moment and the future are just the end of the world. From that moment on, you should understand that there will be no possibility between you and him, but you have been paying attention to his dynamics and want to be closer to his world. You also think it is too humble to do so.
Your present state is like being in a swamp, knowing that you will die if you get deeper and deeper, but you can't help getting deeper and deeper, and the best way is to endure this pain and let yourself climb out of this swamp. And from the moment you climb out, you will find that the sea is vast and there is still a long way to go, far exceeding your ex-boyfriend.
When you are still together, the other person is your world, and you can't help but pay attention to his little things. You will constantly refresh your circle of friends and see his new developments. When he is ill, you will be anxious and want to run to his bed to take care of him. ...
But that was all in the past. Now we are separated, but you haven't fully accepted this fact, and even have a stress reaction, which is normal. All you have to do is endure the pain of this period and try your best to get through it. You have to get through this. This is a very painful process, but it is also a process that has to be experienced.