I think that men probably do hurt as much as women, but they try to hide it, or they try to mask their feelings through hurtful actions. I went through an experience that was somewhat similar. In high school, I dated a guy pretty soon after he got out of a relationship (but it was only about five months). We feel in love, but then he started talking to his ex-girlfriend "as friends". He broke up with me after 8 months, and his ex and him almost immediately became a couple. I relate a lot of the personality traits of your ex to my ex too; he was clingy and "sucked the life right out of me". I also had a lot of friends, enjoyed spending time reading, drawing, playing music, etc. But he couldn't be by himself without going crazy. I realize now that it was a toxic relationship and I"m glad to be out of it. I realize that "true love" isn't clingy and doesn't feel intimidated by you having your own life.
So anyway, in my experience, this guy seemed extremely happy when he started dating his ex. I felt completely betrayed and depressed. But later on, when he realized that his girlfriend didn't listen to him and help him and wasn't as loving toward him as I was, I think he felt depressed as well. This guy based his self-worth off of his girlfriend's actions towards him and has the "I can't go two seconds without having a girlfriend" syndrome. Perhaps your ex is the same way. I think that he does hurt, but perhaps he is trying to hide it. Or maybe he still has you on the back of his mind when he's with his new girlfriend. He might be emotionally tangled between the two of you.
But from the sound of it, this guy seems like he's not emotionally mature and that you're happier without being in the relationship. Take it as a learning experience
Now you can find someone that you can share your happiness with.
Unfortunately, I've seen a lot of guys act in really immature ways after serious relationships end. Guys, why do you do this? (Not all of you, of course. And I know women can act like this too). But I've also seen guys getting out of very long relationships and immediately hooking up with women, verbally abusing their ex, spreading blackmail, mercilessly flirting with girls and posting it on facebook to try to make their ex angry or hurt....It seems like their willingness to move from their ex to a new fish in the sea portrays the message that they didn't care about their ex enough to RESPECT them to give them the time to move on. When you break up, most people have to have a "grieving" period because they've lost a special person in their lives. Do men not go through this or do they go through "denial" where they try to hook up with women to forget about their exes? Could it be possible that women enter the grieving stage immediately and men try to avoid it as long as possible, until it comes back like a boomerang, "Wow. I really miss this person." (Even though I think relationship hopping like this without fully grieving for the person and emotionally moving on causes a LOT of emotional baggage that can't be healthy). What do you guys think?