ステップ姉はあなたのガールフレンドでなければなりません

I am so sick of hearing about your girlfriend and all the things she does to upset you. Hanging out with you used to be fun but now, it's just constant moaning about her. The fact is, I don't think she is right for you. If I was your girlfriend I would never do those things to you. Instead, I would do maybe I should show you what I would do to. Also, what I would let you do to me if I were your girlfriend. So, ditch her and be with me!