Rapid changes of a person's mind.

Today I found some random dude at a site. This site, called bilddagboken, is a site where you post your pictures as a diary with own texts below for everyone to see. Anyways, at first this man seemed fairly alright. He was heartbroken, which was obvious for everyone that read his "diary", and one couldn't help but sympathize with him. Then one checked one or two days earlier. It showed that he had some serious issues! Or at least to me they seemed like real issues. For one his ex-girlfriend had been about 18-22 years old when he himself was in around 40-45. That "overcome-able", age doesn't have to affect a relationship as long as both parts are on the same level. But then one thing prooved that got me real afraid. She had cut off all contact with him at maximum 10 days ago, but they had been friends a couple of months before that, and now he obviously felt really miserable. This far it's all right, still no odd reaction from his side. Then I come to a certain date. He had uploaded a picture of her. There was nothing wrong with this picture neither, but the text beneath wasn't so much pleasant. Below the picture he had written that he had uploaded nude pictures of her onto the web, without her permission, for everyone to see. And he had also written down a description on how to get to that site.
It's disgusting. I understand that he has hard feelings. After all they had been a couple for over 2 years, and it all went from being boyfriend/girlfriend to best friends to nothing in a short amount of time. He even wrote that she had been bad mouthing him to her friends and such, so that must have been really nerve wrecking for him. But he kept repeating in the previous pictures that he loved her, that he hoped it could be the two of them again. How can a person write one day that you love someone to death, and the next post humiliating pictures of the same person on the internet without permission? He really dragged himself into the dirt by doing that. And now he's also flirting with lots of girls that are 19 and alike. Putting pornographic pictures on the same site, saying that he's going to score a lot during the evening and that women are dispensible objects meant to be used.
This man is trying to glorify himself, and at the same time he acts like a full blown jerk.
I can't understand how people can be like that. Change from one to another personality so rapidly. It scares me, and I hate the thought of someone close to me doing that. I like to believe that I can trust people. Though I've gotten to experience quite a few times now that, that is not a truthful fact.

I feel that this certain post is taking more space than I thought, so therefore I'll round it up for this time.