<human>: Give me the gist of the text in a nutshell

Last December I cheated with my boyfriend by letting a guy masturbate to me on webcam with me participating. Yes he's in Texas (the friend whom participated and I'm in NY) and yes he's never done anything like that with me before and I've never done anything like this ever before also, but I still feel horrible about it.

It just started with regular talking and it ended with me agreeing to let him watch me without clothes and masturbate. I felt really bad that day and found an outlet with him when my bf was busy. (I'm not excusing my actions, just giving more background info)

The guilt of it has been killing me. I feel so bad for doing this to him. I always forget about it until my friend talks to me and I remember the situation all over again. I never intend to do anything like this ever again and I've been planning to come clean and hope he doesn't think too bad of me. 

I feel like for 2 teenagers, our relationship is relatively nice. We listen to each other, are functional, and have been very, very happy. I just want some advice on what I should do so I don't completely mess it up.

(And yes I know we're young. That just makes me feel even worst. My first relationship ever and I messed it up. Please give helpful answers)
<bot>: I let someone else masturbate to me and and am extremely regretful about it. Need advice on what I should do.