idk how to go about this
Go about what? Filing for divorce?

Easy peasy - you retain a competent divorce attorney, write a check, and turn him loose.

If you mean sue the boyfriend...no. One more time: New Jersey does not recognize alienation of affection as a cause of action.

Your option is divorce. Or you could try the time tested method of beating the snot out of your wife's boyfriend to make yourself feel better, but then you'd need a criminal defense attorney in addition to your divorce attorney, and that stuff gets pretty expensive after a minute.