Cheating

How do you deal with the guilt of cheating on a really good girl. I never really saw myself getting into another relationship after my last bad break up, But I met this girl who I wanted to fuck so badly but she only has sex in relationships she said. So I pretty much made her my girlfriend just for the sex and I really didn’t care for her at first so I’ve been spinning plates pretty much the whole relationship which is about a year now. Until recently I actually did fall in love with her because she is truly a great person. Now the guilt has consumed me and I often get very emotional about it because here she is being this amazing gf but everything about our relationship is a lie because I haven’t been faithful. How can I ever forgive myself ? I realize now that she’s everything I’ve ever looked for in a partner but I just can’t seem to get over it. Should I let her go ? Can I save this relationship if I vow to never cheat again and be a better me ? The main question I have is has anyone ever cheated multiple times never told, and stopped cheating ? Did it work out ? Just want some perspective from some who’s been in a similar situation thank you if you read all this rambling.