OK, Shopaholic, am fully prepared to bring down the wrath of some of the mumsnetters who have posted on here but this is for you. When I met my dh I was engaged to, and living with, another man. I was very unhappy and wanted out but was too afraid - managing my own despair was easier than trying to change the status quo. I had no love for my fiance, he had killed that with his drinking and emotional abuse, but felt that as I had made a commitment to him, I needed to see it through.
Then I met my dh. He was kind, caring and listened to me. I was instantly attracted to him and pretty much threw myself at him because it was so wonderful to get the affection and mental stimulation that I lacked with my fiance. My dh is a pretty honorable chap and so (kindly) rejected my not-so-subtle advances because, as he told me at the time, he liked me and respected me too much to be an easy-out for a relationship that wasn't working.
I have never felt so torn in my life. I was in utter despair. I felt bound to one man but was head over heels in love with another. In the end, I decided that I couldn't go on like that. I was utterly miserable and would have made my fiance a terrible wife. I decided to leave. It was horrible. My fiance was a pretty nasty bloke towards the end, but I'll never forget the look on his face when I told him that I didn't love him anymore. It was a tough time, trying to explain to people what went wrong. People reacted in every way imaginable. Some were supportive, some people never talked to me again.
It took a while, but things began to get better. Eventually, dh, who had been a wonderful friend through all of this, believed that my feelings towards him were real and we tentatively decided to try seeing one another. It's a few years and two kids down the line now!
I guess the whole point of this ramble is to let you know that there are other people out there who won't judge because they know what it is like to feel torn between duty and love. In my case, it worked out because my dh wanted to be my friend and so even before we became a couple, I knew that he was the sort of man who would always put another person's needs before his own desires. If the man you love can do this, you may be able to get through this together. It won't be easy and it will be painful, but I'm guessing that the situation is already like that for you. There are people here that want to make sure that you are OK and don't care to judge. I think that the people who do judge must be very lucky indeed to have come through life in such a straightforward way as to have never felt torn like this. Take care of yourself, shopaholic.