I'm just really sad today...

I don't really have anyone to vent to, so I'm just going to vent here and write down how I feel. My SO has a friend that he's known forever, and I LOATHE his friend. He's only concerned about himself, he uses my SO and free loads off SO's family because he's like their second son. And he's a complete womanizer, I've listened to so many stories about him and his one night stands, and he BRAGS about "hitting it and quitting it." For a while my SO and this friend quit talking because reasons, and they just recently reconnected and now they're attached at the hip like old times. I feel a bit replaced to be honest, I was SO's main confidant and I sat and listened to him tell the stories about what his friend did, and now suddenly he won't even call me when I'm crying and upset because he's busy with his friend. I just feel like now that he has his friend back, I'm not important... I'm just really upset today and I can't talk to my best friend because my best friend is my SO and we are strained right now because of my issues with his friend. 😕😢