What should this one person do? He feels devastated and guilt?

I don't know who this person is, but let pretend its you at least an example. I know you feel guilty for drinking an having sex, but if you really love someone you wouldn't have done it. What kind of person are you, can you keep a Secret an not be guilty or will your guilty eat you up. The girl can she keep a secret or will it eat her up. You should tell the girl if one of you are going to tell first tell each other first. You decide to tell your girlfriend. You will feel so bad that you want this guy to bash you. You won't want to live. You will be hurting so bad for hurt your gf. You would feel you desired it. You won't feel the pain, because the pain of your gf leaving will hurt more or you could tell the girl you had sex with. You have a plan A. Pretend to break up with her bf and you break up too, do it in a text, they would want to go back, they won't care what happen after the broke up stage. because you both are broken up, you had sex with someone else, don't say who, You don't know it was a party, dark, drunk an heartbroken. You were not together so it won't count as cheating, Your bf or gf will feel so bad an heart broken they would want you back, that's when you tell them what happen at the fake party, they forgive you, still want you back . Problem solved. or Plan B. You can both get them together an tell them what happen, tell your girl friend first, she will tell the guy or Plan C. all 4 together, then I just told my gf I cheat on her with your gf. crying. YOU *** HOLD!!!! PUNCH.. Good luck