FOCUS: To my knowledge, I have not been cheated on. Granted, I have only had one serious relationship that ended in marriage and maybe 3-4 dating ones. Technically, I have cheated. I went to 3rd base with some other dude the night before I dumped one of those dating guys. I did not tell him, and presume he still does not know. He was a sweetheart, if not right for me, so I do feel guilty and still hope he never finds out. Re: monogamy. I've always been monogamous in behavior and emotion, but I'm one of those "don't knock it til you try it" people. I have always had this idea in my head that I shouldn't rule out any of the open relationship strategies, because the important thing is to have a good relationship with your partner and who gives a shit how you get there. So, on our honeymoon, I announced to my husband that he has the option to fuck other people in the future, with the following caveats. 1) Our own relationship and sex life is rock solid. No substituting someone else for me. 2) Other sex partners must be strangers and one-time-only occurances. Physical infidelity, at least the idea of it, bothers me far less than emotional infidelity. 3) He has to come to me and discuss before he goes and bones someone else, because both of the above are always up for discussion. Basically, the way I see this option for him as the opportunity to make sure he's still got it or to find out about the sleeping around he missed out on by meeting me young (he was 22 when we got together). Honestly, I think just having the knowledge that he has an out if he needs one makes him feel a whole lot more relaxed about monogamy, and he may never take me up on the offer. But if he does, I'm prepared to work it out. For what it's worth, the deal does not run both ways. I am not super psyched about this, not because I want to go out and bone some dude, but because I'd like to have that mental out as well. Monogamy, while I enjoy it, is not a piece of cake, even if you're wired that way.
Yup. yup. Yup. I don't want to talk about it. Everyone needs their space and privacy. That said, my inner bell goes off, and I will admit to checking in the past. Sure enough, things weren't right. I'm not proud of it, but...my gut told me to check, so I did...and there it was. As for your situation...I would stay out of it. Those things have a way of unfolding on their own in such a way that you will escape unscathed. You *really* don't want to bear any blame for anything with that.
1. If you are my ex-girlfriend, fuck you Arielle. 2. The emotional dishonesty that accompanies lying to the one you love most is an astronomically shitty thing to do. I can't even begin to describe how bad the betrayal can hurt. If you cannot handle monogamy be a decent human being and talk about it. To you cheaters who actively betray the ones who love you most, go take a head dive off a cliff.
To the original poster, Someone brought up proving your word against hers to your father. Next time you see her cell phone laying around, open the messages, and take pictures on your phone of the conversations on her phone. Download them to your computer, and print out copies. Then, talk to her about it. Tell her exactly what happened, and exactly what you saw. If she denies it ever happening (which probably means she's cheating), take the copies out of your pocket. If she acknowledges the texts and reasons them out to you, tell her your appreciate her honesty. Either way, explain to her the dilemma you're in. Tell her what you think will happen to her, and tell her what you think will happen to him. Have a long conversation, and by that, I mean not one-way. Allow her to talk as well, and listen to her answers. But make it very clear to her that, whether she's cheating or just receiving weird texts, she needs to talk to your dad about it. I know you're in a terrible position right now, but it could get a lot worse if you don't ask her about it now.
Breaking this down: It's understandable you don't want to talk about the first two situations, but #3 begs for elaboration...