I've been hesitating to post my question because I'm quite embarrassed about it, but I've finally given in, because I'm curious about the opinion of others. I'm about to get engaged with my girlfriend of over 4 years (we're both in our mid twenties). We're planning on getting married within the next year, and I'm planning on proposing and making it "official" within the next few weeks. We really have had a wonderful relationship in many ways, and I'm certain that she's the one I want to spend the rest of my life with. There's just been something that has been on my mind. About 9 months ago I cheated on her once. I slept with another woman. It's a complicated story (are any cheating stories not?). For quite some time I couldn't understand why I did what I did, and felt quite guilty about it. A lot of it I believe was because my girlfriend and I were talking more and more about marriage and the ultimate commitment, and I began to have fears about it. Not, specifically because there was anything wrong with our relationship at the time, but I'm young, and facing marriage made me nervous. It was coincidental that at the same time I became quite attracted to this other woman, and though I did my best to fight all of my urges, I eventually caved in. Again, nothing was wrong with my relationship. Looking back, I feel that it was all of my stupid doubts. My girlfriend never found out, and I have no plans in telling her. The only other person that knows is the woman I slept with... I've never told anyone, and plan to keep it her and mine secret. I don't think the other woman would ever tell, but I guess now I have a little bit of a doubt because of my upcoming engagement. I know that my girlfriend would be completely heartbroken if she were to find out, and I can imagine that she would then begin to reconsider us getting married. Am I making a mistake by not telling her? Just wondering other people's opinions. Thought this site might be good, since I haven't discussed this with anyone at all, and do not have any desire to let anyone in my life know. Thank you for your thoughts. And, please... No attacking me for what I did. I regret it, and it was a huge mistake that I believe I have learned from. I'm human!