Hi I need to break up with my current girlfriend for reasons which I will explain soon. I was wondering what everyone thought of this as a possible conversation "So I wanted to start off by saying I'm sorry and if you hate me after hearing this I will understand. When we started out dating I was simply scared of who I really am and I hoped that maybe you could of helped me change that but now I see I can't hide from myself and I need to come to terms with myself. I am gay. I somewhat always knew this but I was scared of what society and my family and friends would think. I am sorry for pulling you into this mess of a life but I want to end dragging you along before I hurt you to much. I feel terrible for all of this. I do not know if I am ready to "come out" so I hope that I can confide in you with this secret until I am ready. I hope we can continue our wonderful friendship that we have. "
That sounds very light hearted and sincere. I wish you the best of luck for you, some people will be slightly hurt and understanding, others will be hurtful and vengeful. Just be prepared for either.