Separation anxiety

How do you stop this. Literally everyone and everything I love gets taken away from me stabs me in the back or dies. All I have is my husband. I try to let him have a life outside of me and go do things with his friends but I get so anxious. He wanted to go on a weekend guys camping trip with his cousin and brother. I want him to go and enjoy himself but I get panic attacks just thinking about him being that far away for a whole weekend without cell service so I can't even talk to him. We have been married for 3 years and he hasn't been gone over night in that time. I don't want to be a control freak and say he can't go do thing without me but I need to find a way to calm my anxiety. I have no fear of him cheating or anything like that the fear if that something happens and I lose him. Can anyone give me advice on how to relax a little bit.