How to prevent from saying hurtful things?

[Hugo]

I got a question..How do u stop yourself from saying hurtful things to the other one when u in a heated about to break up conversation. When the girl is telling me she doesnt want to be with me over BS reasons i go pretty ape s***. I cant seam to stop myself cause its such crap. For example, i use myspace and my girlfriend at the time did also. WEll this girl she doesnt like put a comment on my comment baord about hanging out sometime and wondered if i was still alive. The reason that girl wrote that cause i dont talk to her cause i know my gf doestn like her and gets jealous. Well what do you know my gf calls me the next day accusing me and questioning me about that comment saying "go ahead hang out with her, u dont care about me anyways" I went crazy cause that was such a load of crap. I dont even talk to this girl and i went off about her not using her head and she doesnt even think and all this stuff. I suppose stuff like that when i get blamed for dumb crap that I go crazy about. How does one stop themselfs. Maybe im the stupid one