My friends boyfriend cheated on her!?

[Lizzette♥]

So i just found out that last year my bestfriends bf cheated on her.
Lets call the girl L, my bestfriend R and my bestfriends bf O
There had been rumors about it at school last year, but he denied it. He was in band and the band members had told her that he was cheating on her but he denied it saying that they didnt like her.
So now my sister told me that she was friends with Ls bestfriend and they ended up talking about R and O....Ls bestfriend said that O cheated on R with L but that R knew already cause they told her but thats not true.
Sometimes O would delete everything on his phone before giving it to R and L would only put pictures she took with O on facebook and not with other friends.

So what do u guys think? Did he really cheat? Or do they just wanna break them up?
Should i tell R something?

My mom says i shouldnt tell her anything since we're not sure if he did really cheat. What should i do?

Please help

Thanks in advance!

[Lazy-assedbeam166]

tell her there's a possibility that he may have cheat on her.
but she may get mad at you