My brother and I lease an apartment together. One day, he bought 2 PlayStation Vitas and I took one from him without paying. He was single, so he saw those as a past time. He got really mad to the point where he started to flirt with my girlfriend. He then kissed her and slept with her. My girlfriend had an affair with him for a while and then dumped me for him. Since my brother and I live together, she ckmes around often to sleep with my brother. What do I do?