My very good friend has been with her current boyfriend for over 3 years (he's a former alcoholic). He's cheated on her before and she's caught him, faught, broke up, he apologized, and she took him back. Each time she has taken him back and things for them have gone back to normal. She says that she can tell when he's lying, and that he never lies to her. I've caught him in a lie before that she doesn't know - obviously she doesn't know when he's lying. I've caused problems in their relationship before without meaning to, so I've stepped back and kept my mouth shut about the whole thing for quite a while now.
Not too long ago, I found out that they had been fighting and that she kicked him out of their house. I found out, because he drunk texted me instead of her. Our names are on opposite ends of the phone book, and I very rarely text him ever. It's not like he accidentally clicked on my name because it was next to hers in his phone, or he replied to a recent conversation of ours. He had to be completely wasted to select my name from his phone. In his drunk text he refused that he was drunk and said some other stuff that led to me finding out what exactly happened. I replied to his text just so that he would know text his girlfriend right away instead of waiting for a reply from the wrong person. He replied with "oh shit, sorry. shhhhh" with jumbled up letters, but still legible. To this day my friend does not know that he accidentally sent me that text first.
She took him back. Before she kicked him out, her friend at work guessed exactly what was going on right away just from my friend talking to her about the situation. She was so shocked that she guessed it right away, and that she herself didn't even think that he had been drinking. She's so blind to things with him.
My question is this: if I know things, and realize things that she can't see about her boyfriend, should I tell her? Recently, she told me a story about something that happened with her boyfriend. The story seemed a bit ridiculous and far-fetched, but she believed it 100%. I, however, guessed something else was going on right away, and I'm almost positive I'm right. It involves him cheating once again, and receiving a gift from his "other" girlfriend - which he made up a story for that is absolutely ridiculous. He claims that some old lady dropped it off at his work when he wasn't there for him, and that he doesn't know the lady. He claims he watched the security tapes of her dropping it off and he doesn't recognize her. The gift has his full name and birthday engraved on it. Sounds a lot like another girl gave him the gift, and he had to make up a story so he could keep it.
Any thoughts/advice?