Any advice here would be greatly appreicted as this is turning me into quite frankly a mess. I met a girl in a bar 4 months ago.. we ended up hitting it off, seeing each other more and more regularly, having sex, etc. However there is a catch. She, from the start was in a relationship of 2 years, we both knew this. When we first met she spoke down on him and spoke about how she needed time to get to trust me in order for her to consider ending it. She has known him for a long long time and is fully integrated into his family, good friends with his mother and brother. I found this understandable as if he didn't mistreat her and she was deeply involved with him then it would be hard to just drop it all in order to be with me with the chance of it all turning sour in a short period of time. It seemed to me like the spark she had with him was gone and only if she was certain I was a better alternative would she make the change. So I let this continue, and continue, until basically we both loved each other. But she still loved him too, even though she was going behind his back. This became more and more stressful and resulted in us bickering and arguing quite often, until last weekend I couldn't take it any more and told her that I need to know something is going to change one day. This has now led to her basically having a breakdown and she has decided to call it off with me as she is still not ready to abandon a huge part of her life for someone of 4 months. She told me that she can't keep doing it and hurting me by not committing and hurting him, even though he doesn't know. This has destroyed me and for the last week I haven't slept and feel ill. I know that she still loves me as well as him, and I can't go and tell him, the poor guy, because I know that would finish things with me for good and I can't do that to her as I genuinely love her. I also know that the situation is recoverable, I'm just not sure how.. this sounds like she is playing one horrendous game and is playing us both but I can genuinely see how much it is hurting her to deal with it and take this decision. The question is what is my next move.