Spadly said:
It sounds like you're a bit of an overprotective cockbend, so he was probably trying to avoid telling you that he was boning your sister so he wouldn't get his ass kicked.
Honestly, it's okay if he's doing your sister. Be okay with it.
Yeah, he kissed some girl, we all make mistakes.
Also, the "Bro Code" does not apply to sisters. It applies to potential sex that your mate steals from under your nose. THAT is an ass-kick-worthy situation, not this.
Leave them to it, it's not really your place to poke and probe. Your sis is old enough to know what she's doing.
Clearly you've never read the bro code. You don't date, much less have sex with, one of your bros siblings. There's too much potential drama, and it's especially something you don't do without getting permission. Yeah, I know, the sister gets to do whatever she wants, but sisters go (for me) in the same category as exes: possibly, but only with the blessing of the friend.
OP: If you find your friend's behavior abhorrent for any reason, you have the right to call him on it. You get to tell him what continuing to be friends requires, and you get to set limits for behavior. People will tell you it's not of your business, but that's crap.
BonsaiK said:
This is none of your business. It's between your friend and your sister. Talk to your sister about what you saw if you want, but don't be a macho dickhead and try to intervene. either physically or in any other way. Let your sister make her own decisions about who she wants to see, it's her choice at the end of the day.
How would you like it if you started dating some awesome girl and then her brother kicked your ass for no reason other than he didn't approve of you? It'd be completely stupid, and none of his fucking business, right? RIGHT.
Bonsai, you know how much I respect your work on relationship drama threads, and that I have all due respect for your qualifications to give advice. Thus, it is with only respect, that I tell you that you're completely full of crap on this particular issue.
Yes, it's the sister's choice of who she dates, and it's the OP's choice of who he wants to remain friends with. From my reading, the two parts of this are:
(1) his friend hid his interested in the OP's sister from the OP and his friends, while dating the sister on the sly
(2) the friend cheated on OP's sister.
To the first: OP has every right in the world to say "that shit ain't right" both to his friends and to the violator of that most sacred of codes: the bro code. While you're correct the friend and sister get to decide who they date, the OP also gets to decide who counts as a friend... And someone banging my sister is unlikely to fit that bill.
To the second: I accept in general that bravado isn't going to win the day, but as per the first point, there's nothing binding the OP to remain friends (or even civil) with a person whose actions have been distasteful.