Broken Hearts

Im sure everyone has experiance one of these, although some not as much as others depending on wether your the Broken Hearted or the heart breaker.
In my experiance I have learned one thing, when your heart gets broken by someone they become a total arse.
This has happened to me a number of times..and to be honest I just cant understand it.
My latest boyfriend broke up with me cause he couldnt handle a long distance relationship, told me he wanted to stay friends and even was polite enough to respect my wish to not talk to him for the time being.
A few days later he has already found a new girl friend, who I feel very sorry for.

Today he added me and my friend along with her friend to a group convo and started having a go at all of us.
If anyone can tell me why some boys act this way I'd be quiet interested to hear your opinion on the matter...

By the way Im sorry if this offends anyone but as stated only some boys behave this way and Im definetly not saying you all do...