BM throw it back on close friend

My baby mama & I grew up in a big friend group & one of our friends used to always hit on her when we were younger, but I got it her. Fast forward some years later, we had some kids & had been on & off for a bit. So suffice it to say due to such, she had gotten thicker (fat ass, thick thighs, fat coochie) So that same friend came to home from the military for a bit to visit. During this time, we were on a break as we had gotten into an argument. So when we met up, I told him of this. He, sounding like he was being nice & looking out, said he’d go talk to her for me. The next day he told me he did, but he was kinda distracted as he hadn’t seen her in person in some time & noticed how she’d grown. Me, having grown to like the idea of her with other men as we’d had talks about it during our breaks, I told him to go talk to her again that night & try to see if he could seduce her. He agreed. So later that night, around 2:43am, while I’m scrolling social media, he sends a message to me. I open it & I immediately get rock hard. It’s a video of him & my BM, her thick lightskin cheeks bent over, throwing it back & forth on his dick. The video & the idea of her submitting, giving it up, throwing that creamy, fat pussy on him & having no idea I know made me bust the fattest nut. To this day, she has no idea I know & he’s hit it once every time he comes back to visit, always leaving her cheeks covered in cum. I hate how horny it makes me.