UM, your wife wants to come back to you, but you are so frightened by the “boyfriend” that you won’t let her?
You need to take your wife back, go and get a restraining order against this guy and do what needs to be done to protect yourself and your wife.
Move to another location if necessary.
Your wife messed up big time, but are you going to be ok with it when this guy harms her or kills her? Are you going to be able to live with yourself?
Fred’s wife sounds like a total loser, a drugged out loser. Why would he want her back? There are good women out there Fred, go out and find one of them.
Best of luck to you Fred!