Dude, three times!!!!! It doesn't matter if that happened 3 yrs ago or longer, but it's three times already. Bet she prollie must have do the same as mine did, cry her way out and as a result of ur weakness, she now must still be taking advantage of u. Who knows how she's gonna react when you tell her, she might not even care or laugh about it. It would be hypocritical if she got mad at you, wut she did was worst than wut u did. At least u didn't kiss nor * * * * the other girl. And why on earth are u even considering marrying her?, IMAO. But ok dude, that's ur choice, if u wanna date a cheating liar, then do so. But yes, u gotta tell her, if u feel bad about it, tell her. I'll bet she won't even care.