Hey guys, i'm going straight away, i thing my sister's boyfriend is cheating on her. Ok, i don't mind the fact that he is cheating on her. We grown up together and i promissed him that i would be his little SISTER over everything. Even if he cheated on my sister i wouldnt tell her, because that would mean betraying him.

The point is that we've gone out a few times (my bff, my sister's boyfriend, and I), we went to the cinema and to the mall secretly because my sister is kind of the jelous-type.

My bff started going out with a guy , and she doesnt wanted to show him to me, neighter wanted me to listen to his voice. I founded it suspicious, so I thought he was really gross and disguting xD.

My anxiety came when i overheard a conversation between her "boyfriend" and her, and his voice sounded exactly the same as my sister's boyfriend.
I couldnt get calm and that worried me, i mean, lived with him for 6 year, i would recognize his voice from 10000000 miles away.

Today she was talking with him by the phone and to end this anxiety of me, i called my sister's boyfriend. If course if my bff was talking with him, he wouldnt be able to talk with both of us at the same time, so she (my bff ) would have to wait.
They were talking vividly and she was telling him a story, then
He picked up and we were talking, sudenly my bff stoped talking, it was strange...

Then i hunged up , she started talking again.
Then i called him againg using some cheap excuse, and she got mad and stopped talking again.

I thing they are going out :S what should i do?

I'm sorry if it was hard to understand xD

I think you should confront them (keep your sister out of this for now,) but first I think you need some more evidence. Be 100% sure and then confront them about it. If they still want to keep it a secret then tell your sister to break up with him. I hope I helped ^^ and good luck! :3

>>2 of course they're going to want to keep it a secret. How naive can you be? Do you expect this guy, who has no problem cheating on his gf, to suddenly gain a conscience and confess?

OP should blackmail them.

Miss Fu,
This goes beyond loyalty to your brother or sister, in my opinion.
If your sister's boyfriend is cheating on her, this is immense disrespect to her as a person. It's not about whether she's a jealous sort or whether they deserve each other. Lying to someone who has given their heart to you is the worst sort of behaviour. If your brother/sister's boyfriend likes your bff more, then why doesn't he just go out with her instead? Why would someone deliberately put someone else in potential misery to make themselves happy? Sounds selfish, huh.
And lucky him, he's got his poor girlfriend's sister and possibly only ally on his side too. So your sister has no one who will support her when the time comes and her heart is crushed. Are you this heartless?
I surely hope not.
You know what you have to do. Get down to the bottom of this. Get all the facts. Ask your sister how things are. You don't have to be very obvious. See if she's noticed anything. And if she has, ask her more about it, so at least she'll be prepared when he finally breaks up with her, if he's cheating that is.
Please ask your bff very clearly if this guy is the same guy that your sister is dating, and if it is, ask if she knows that he's actually dating someone already.
It's possible that your best friend thinks he's dating her but she's just misunderstanding the situation. Or maybe he's being immature and thinking he can have two women to himself.
If this brother of yours is doing something potentially immoral that will break the hearts of other people, then I suggest you rethink what being a sister is about. Being a sibling goes beyond just blind loyalty. If he is going down the wrong path, you MUST correct him. That's love - saying what needs to be said even if you know they'll hate you for it.
Good luck.

>>4 I agree 1000%

seriously 'REAL' family should come first not a two timing jerk by doing nothing your betraying your 'REAL' sister where is your common sence

>>5 Please follow this person's advice!!!

best friends only last a little while family is eternal you should honor your sister and tell her you would want her to do the same for you

Thank you guys.. But i dint know if confront my bff, because i'm not sure if the person she's dating is the same as my sister's. so i'm afarid i could hurt her feelings if it isnt the same person ),:

Next weekend they are going to the mall (my bff and his boyfriend) , she told me so.

I'm going to follow her ),:
I need to confirm and end this anxiety of mine

Good luck, I wish you the best ^^

Update us on how it goes.