I made the horrible mistake of lying to my boyfriend. When we first got together, I had told him it had been a long time since the last time I had sex with someone.

Unfortunately, that's not true.

I ended up sleeping with someone a month or so before I met my current boyfriend. The person I slept with is an ex. (I want to reiterate that I did this BEFORE I met my current boyfriend.)

The fact that I did that isn't what bothers him. It's the lying to keep it from him that kills him. I feel like an awful person, but I just wasn't sure as to how he would feel about me if he knew I slept with someone I wasn't in a relationship with. All my life I have lived by the philosophy of only sleeping with someone you are in a monogamous relationship with, and one drunken night, I made the mistake of breaking that belief.

I feel awful for lying and will do anything to make this right. Any thoughts on my situation? What should I do to help get us back on track?