Let me start off by saying that I am not new to pick-up, despite my lack of posts. In fact, I'd say I'm a pretty fucking great PUA, it's just I'm more of a silent-observe and learn type. I only post when I have something I need advice on... Unfortunately for me, this is one of those times.
Currently I'm dating three people. (We'll call them Sam, Marina and Erika.) And no I'm not cheating on any of them, they all know about each other. (Thank god for open relationships.) One of the girls, Marina, is absolutely amazing... I can honestly say that I think I might be in love with her, and that thought scares the living shit out of me. I know talking about "love" to the PUA community might not receive the most positive reaction but hear me out. At first I thought I might just have Oneitis for this girl, so I tried seeing other people, thinking about her negative traits, everything I've done in the past to get over Oneitis... none of those worked. When I talk to her, my thoughts aren't "How am I gonna get this girl to fuck me?" My thoughts are "How am I lucky enough to be with a girl this amazing?" Definitely not oneitis... Which leads me to believe that is in fact love. Anyways now that you have a bit of background to the situation, here's the issue...
She's the only girl, out of any girl that I've met in a long time, that I'd be willing to be in an exclusive relationship with. Only problem is she's in an open relationship too... Normally I'd be okay with that, I know everyone she's with at the moment, and I think all of them are awesome. She's even with Sam, one of the girls that I'm with. (She's openly bi, and dating a girl that I'm dating. Three way opportunity? I think so

) Anyways everyone she's with is really awesome except for this one guy... I honestly can't stand the thought of sharing her with him.
Here's the thing, I'm 15, she's 14, and everyone she's with is somewhere between 14 and 16. Except for this guy who I hate (we'll call him Daniel) who's 20. I'm sure you guys can see my problem with Marina and Daniel being together. Me and Marina have talked about her and the people she's seeing at length, and I can tell she really does care about Daniel... only problem is he doesn't really feel the same way about her. He's a fucking pedophile, plain and simple. I even discussed it with him, the only reason he's with her is because she's willing to have sex with him. The real irony of it is that he's the only person she's ever had sex with, and she's doing it because she thinks he loves her when really he only wants her for the sex. Of course I could never tell Marina he said that, and even if I did I doubt she would believe me...
I need the PUA communities help here. I want to get Marina away from him, but I'm not calling the cops on this guy for his pedophile bullshit, Marina would never forgive me if I did. I need the best BF destroyers you have, but they need to be subtle. I have to take this bastard down, make Marina break up with him, but it'd be best if Marina didn't even realize I was doing it. Even if you don't agree with the whole "love" principle that I'm doing this for, you have to admit the situation with Daniel and Marina is fucked up on its own accord. 20 and 14. Thats not okay. Anything you guys have to offer here would be appreciated...