We live in nj. My soon to be exhusband has belonged to multiple sites for dating since a year after our marriage, furthermore, one of the sites that he was an active member of for several years was a beastality dating site. He even wrote in his profile that he had the opportunity to meet some of these people while travelling. Is there anything I can do to prevent him having overnight visitation with my kids? I am concerned about the people he has been interacting with.

Probably not. You can bring this up to the court, but I doubt if its sufficient.