Why do I feel so damaged.

I feel like I'm broken beyond repair, that is ruined myself psychologically and physically. I feel ashamed and guilty of my actions, I feel disgusted with myself. I've ruined the one relationship that meant anything to me. The bond of trust with my girlfriend has been destroyed because I lied about touching myself out of shame. She won't forgive me and is probably leaving me and I feel like I'm losing all of me. She's taking the kids with her and I know I will fall into a deeper darker pit if she does.