SHOULD A BITCH SNITCH?!

Some dude I was seeing like a year and a half ago just got engaged to his current gf. She seems extremely nice & I've heard nothing but great things about her.

But dude was in my dm's a few months ago sending me pictures of his mediocre thrift store dick WHILE HE WAS WITH HER

I didn't know they were together still when this happened at all

I know it's not my place, but I also know he's a cheater and he's manipulative and just an all around shitty guy and that will never change. I can't help but feel bad for her, she deserves a lot better

Follow up question: how can a bitch snitch without getting directly involved?! I think the right thing is to say something, but I don't want the drama.