I lied to my girlfriend and now I feel guilty. (NSFW)

I’ve been with my gf for 8 months now, and I have fallen in love with her. But we both have an issue, I pee the bed at night (I’m 21). She knows about it and I have bought adult pull-ups for her. She has never used them. But last night I was sitting on the couch and I was eating dinner, and I felt the urge to pee. I told her I had already pee’d but I really had to pee. I told her that I had to use the bathroom, and I went to the bathroom, but I didn’t pee. I went back to the couch and sat down and started to eat. She was laying in bed watching tv, and she asked if I had used the bathroom, and I told her I did, and she asked if I had peed, and I told her I had. She started to cuddle me and lay her head on my shoulder, and we started to kiss. And then I felt the urge to pee again. I went to the bathroom and I had pee’d. I came back to the couch and I told her I had to go use the bathroom again, and I went to the bathroom again. I had pee’d again. But I feel so guilty. I lied to her and I don’t know how to tell her the truth. And I’m afraid that she will leave me. I just don’t know what to do.