Lost and puzzled please help

I am at a very confused state of mind. I have met all the wrong guys in my life who does not cherish me and treat me badly till the point where I get tired of relationship and wanted to give it a break. I have been two time and faced the hurt and pain all alone seeing my ex going out with other ladies with my own eyes. I couldn't more describe the pain that I went through. Though things are over some memories will always be etched in your mind , though I don't hate them or feel anything for them but it always serves as a reminder to me for my future relationship.

Then a guy came when I just wanted to concentrate on my life , a guy came I would say no one is perfect but by far he is the nicest guy that I have met so far, he gave in to me. And because of my prior experience I have turned into another person who is tired of giving because honestly I am very afraid of being hurt once again. I don't dare to give in again but yet I must confessed that I truly have feeling for this guy. We have been together for three years.

Problem arises recently when he is busy at work and I am busy with my own life. I couldn't believe something that I did mistakenly. I swear to god that I never want anyone to be hurt but just then someone who resembles and have all the features of my ex came by and became my colleague.
We begin as friends and there after , that guy actually expresses his interest in me. I told myself that I love my bf and I won't do anything to betray him. But then things move on further, we progress through the months because both of us are facing relationship problems and we treated each other as confidante. I warned the guy about the hurt that will be caused but then he keep convincing me that everything will be fine. We could just leave a happy life. But my conscience and everything tell me one day the truth is gonna be out and more people are gonna be hurt. I swear and i really swear I never wanted to jump into it but at my weakest moment he was with me and he helped me out with the problems I had with my bf. I am really grateful for what he did. I enjoyed the time spent with him but deep down I know I can't accept him because he just resembles my ex and has all the features of them. I know it is only temporary and won't last. I want to put a halt to everything but I can't.

everything was simple caused by my inability to be hard hearted. I hated myself alot. I feel remorseful and horrible each day , self reproaching myself but I have no one to turn to. I am a good counselor to my friend but deep down I am not a good counselor to myself. I love my bf and I truly hope that things within me n bf can work out as there are problems between us. The problems are unresolved which causes me to be fall into the trap. i wanted to confess eveything yet I know if i were to tell the hard truth, it will mark the end of my relationship with my bf. What should I do. I am lost. I wish I could be like before not wanting anything but in the end I can't give up. Afterall, I am emotionally weak to be make used of to make the wrong decision and to commit something that I hated myself so much and to put other through the pain that I once went through. I really would like to seek for forgiveness and wished everyone will be happy.
But things doesn't seems easy.

I am determined to put a halt with the guy who is interested in me but somehow I really hate myself for not being able to be mean. To tell him to ignore him and feel that I am their emotional slave. I am tired, really tired of all this. Could someone please help me out. I really need your advise. Thank you so much.

Wonder if any lady out there faces the same situation and could please advice me? Thanks in advance.