I've been lying to my husband for 10 years and I want to tell him but I'm afraid of how he'll react.

My husband (38M) and I (36F) met in college 14 years ago and we've been married for 11 years now. Once, we were at a party where I met one of his friends (25M), and we had some kind of sex. This happened once, and afterwards we agreed not to tell my husband about it, as it was a one-time mistake. I haven't seen him since the party, nor have I ever contacted him. But in all these years I've felt guilty. I want to tell my husband, but I'm afraid he'll misunderstand. Should I tell him or just let it go?<br><br>&#x200B;<br><br>EDIT:<br>It was a mistake, and I wasn't trying to hurt him. I want to tell him because I want him to know the truth, but I'm worried he might start a fight. I want to know if there's a way I can tell him without causing trouble.