Are you asking if there is a legal mechanism that you can use to keep your wife from seeing her boyfriend in another state? No.
Unless there is a court order to the contrary, she is also allowed to take the child there for visits.
If they're having sex in front of her or the guy is a child molester or otherwise dangerous, you can get the court to stop letting her take the child there.
But the mere act of having a boyfriend and visiting him is not sufficient for you to use it to keep her from contact with the man.
If you are concerned about the child's safety, you need to ask the court for a hearing on temporary custody, vistation and support issues and try to get it written in such a way that she cannot take the child to his home. But your chances of getting that restriction are slim if there's no big danger, just your angst about it.
Sounds like a tough situation. Hang in there....