My gf for 3 years has a sister which is also a close of mine since shes the one who always defend us whenever her sister cant come home after a night. One time we 3 are out together. I noticed her sister is very clingy. Touchy. And always compliments me and how good of a bf i am. And if i ever cheated on her sister. I replied with the truth. Nope. And she always teases me. That i can tell her the truth she wouldnt let my sister know. So i smiled and told her the truth is no. I am busy with work and only have time for her sister. She jokingly said. I wouldnt mind if you cheat on her as long as its me. I was shocked. Then she kissed me on the cheek. When her sister came back from the rest room. My face was pale. And her sister signaled to...