My ex told his sons that there is a sex tape of me out there

I'm really fucking annoyed right now. I left my ex husband months ago because he is such a liar and an overall POS. I tried to have him spend time with his sons. He kept making excuses on why they weren't coming over for visitation and I was trying to make sure he got them birthday gifts and he kept saying don't worry about it. It wasn't until both his boys blocked me that I thought something was up. He said they're just hormonal teens. Nope. He was telling both his sons and their mom that I'm the one who doesn't want them there. That I blew through there birthday money on gambling. He lied and blamed it all on me. I actually posted about it months ago and got a stupid comment saying that wasn't a reason to leave him. That him being a good father has nothing to do with our marriage which it does. I don't want a POS deadbeat who's gonna blame me for them being a deadbeat. He tried to gaslight me when I saw those texts of him blaming me and lying and refused to tell the truth so I told the mom and sons I care about them and that wasn't true. My husband kept lying saying It was me but after we split up and he continued to be a useless deadbeat they believed me. They message me here and there. Tell me how school is going. They got a girlfriend. Etc. Well most recently the younger one who is FIFTEEN sent me screenshots of there dad sending them a video saying how I'm going viral. Some sex video was leaked. They told their dad that's not me and he said it is. He can tell from my ears. No it's not me. And his son sent me the message to let me know my ex husband is telling people I got a sex tape leaked. First off it's not me. Second of all of it was why the fuck would you send a video of a sex tape to your underage son. He's a fucking weirdo! We've been split a while now. He had a whole new girlfriend. Granted I heard they recently broke up but it's like that happened and he decided to just fuck with me. Especially now that I'm in a happy relationship and I love my boyfriend. Wtf?

Edit: they're his kids. They were my step kids before I left him. They still talk to me though