Search Results: how to tell he his hiding something

(I'll make this vague but detailed, this took place within a months time span and I'll share the more important facts.)

I overheard two girls talking about my friends GF, they said that she had been saying she was single and lying about being in a relationship. They were unaware that I knew both the people they were talking about (so they were completely candid).

The 1st thing I did was ask the brother who lived with them, he felt something was off, he said they were always apart and she was always going out.

Then I told the GF what I heard, her response was robotic (hard to explain almost like fake disbelief).

Then I talked to one of the girls, she gave me more details of cheating, when and where.

A silent feud started and I became the messenger in a war of words, I got more details from the other girl, things eventually got more heated then the shit hit the fan.

- There's evidence going against both sides, proving her innocence and proving she was cheating (I'll never know because no one confessed) the GF might be innocent because I think living a double life is too difficult for her because she's terrible at hiding her emotions.

I had a talk with both of them privately to reslove the issue, I actually managed to work things out... or so I thought.

Eventually after several months they broke up, he said he felt her growing apart for the last few months (that conveniently match up with the incident)

After a few more months I tried talking to my friend about it but he refused and was reluctant and said it was all good... until I found out he fucked me over on a business deal (he told a mutual friend and it got back to me) and the reason for it was because I believed the rumors that I heard about his GF.

So now I'm not talking to that friend because I'm pissed that I ended up the bad guy because I overheard a fucking conversation & I'm not sure if I want to repair the friendship.

I just wish I knew the truth for my intuition's sake.