So your brother is your step brother, or am I retarded (don't answer to the second part only the first!)
Your bro is a douchebag, write him off or laugh at him and your ex as that is pretty funny (but not in all actuality) it should make you feel better for a short period of time. Keep in mind man the girls definitely aren't worth all the grief they give. You want to let some pain off go get a crotch rocket and open her up on a freeway, that is some nice relaxation and great way to feel better (don't do anything too stupid though!) Put some headphones on and you are officially in a different realm!
Don't worry everything happens for a reason! (no pun intended)