My little brothers girlfriend has been having sex with his friend??

Dude,

Shit or get off the pot.

You obviously care a good bit about your brother to make numerous threads and still be posting days later. May I ask how you know this information? Do you see it with your own eyes?

The longer you wait the harder it's going to be and the more hurt your brother will be by all of you. To know and not speak up you are just as guilty.

If you are worried about him not believing obtain some kind of proof. I'd rather tell him and have him not believe it, than not try at all.

You two will be siblings for life, this broad is likely temporary. Do you really want him to remain fooled and marry this chick down the line?

I'm starting to wonder if this is a troll post.

Either A. Tell him or
B. Dont.

Don't over think it and make it difficult. "Hey there's no easy way to tell you this but I saw your girl with xyz and she cheatin"

 

Lmaoooo celeste this is hilarious

 

Go get some dick and leave those kids alone. You obviously have to much time on your hands if u worried bout others relationships.