help plz

[!!!!]

you guys i cheated on my fiance with another girl!!! she was all like "wanna do it" and i was like "okay sure" and then we lit some candles and oiled up and ATE A WHOLE CAKE and then we made out and then we built some kites but we didn't fly them then we decided to save them for later and then we oiled up some more because most of it had rubbed off onto the kites and the stuff in her apartment and we DID IT i guess idk what it was but anyway i feel real bad about it what should i say to my fiance!