Awkward situation with my buddy, his GF, and my Ex

[HighandDry]

I met some very cool people in my two year stay in California, my buddy Miguel, his girlfriend Brittany, and my ex-girlfriend, Blair. (Brittany's, and Miguel's former best friend)

Miguel and I grew close, he always confided in me that he'd been sleeping with other women off and on during his three year relationship with Brittany. Not to mention, he loved strip clubs, and gawking at other women. He never really seemed ashamed of any of this.

I've never told any of this to Brittany, didn't want to get involved. Until recently, Blair found out, and confirmed through me that Miguel has in fact been sleeping with a co-worker, one who works with Miguel and Brittany. Blair is super protective of her girl friends, and made Brittany aware.

As I figured, Brittany, denied this, didn't believe Blair, and sided with Miguel. Miguel played dumb, fed Brittany a bunch of [censored], and promptly took her to Vegas. He's super conniving, manipulative, and persuasive. Brittany falls for his [censored] all the time, she loves Miguel, and doesn't want to see a three year relationship crumble. They share an apartment, two cars, and have talked about kids. She's in denial.

Brittany has basically removed Blair from her life, and Miguel is super pissed at Blair for "trying to ruin a relationship", Blair is now considered a "man hater", and a bad guy.

I've stayed out of it because I live 2000 miles away, don't want to get involved, and feel that I shouldn't. However, I have told Blair what I know, and expect that she doesn't reveal me as the all-knowing third party. I'm playing Devil's advocate, and keeping my mouth shut.

Blair knows she's done all she can do. If Brittany is going to fall into denial, and dismiss every claim, that's her fault, she'll end up getting hurt, but she'll find out for herself later on in life.

How would you play it? Tell Brittany what I know and face Miguel knowing he's gonna flip out, probably threaten me with [censored] claims, and nix me as friend. Or, hang low, and stay out of it?