>>33303426
Document text messages about him doing this and if you can contact him and try to secretly record the call and get him to admit to it
If you're in the US and depending on state there are revenge porn laws, leaking nudes if ex/current partners without their consent is illegal
You can also get into contact with various legal firms that take care of this, common issue so many exist
They typically will(and you can if you want to as well) email the hosts/owners of the websites and sometimes the server owners, let them know they're hosting illegal material and threaten them with lawsuits to get them removed