been trying to let her go... I was cool when I thought her relationship was over but now that I know its not I am not detached anymore.
You don't need to be detached. You need to think about your values, your goals, and then plan on how to honor and achieve them. Detaching can help, as it'll prevent your emotions from clouding your judgement, but it's not a necessity.
A wise man once said "Do the right thing, as if Jesus himself were standing next to you."
