This may sound strange but I have been working on retraining my neural pathways. I have read about traumatic situations or prolonged stress trains our neural pathways to stay alert to danger and that actively working to destress we can "retrain" them. I have to say, this isn't easy but it helps. There is some science article on this somewhere on the net, which is why I started actively working on it.
Much like Chubbybunny said, we have an anxiety response for a reason but our minds don't know when to let down it's guard sometimes. But we can work to fix this by repeatedly sorting out our thoughts and putting them in their appropriate place. If you say to yourself, "he's fishing and that's it", chances are you will find peace with that but if you let those thoughts run unchecked and uncorrected, you will make yourself a mess and that anxiety will reach newer heights until it paralyzes you.
Now, look at it from his standpoint, what has he ever done to deserve this questioning of his love and devotion? If nothing, ask yourself....What's it going to be, choosing anxiety or choosing to trust him? Which one will lead to a better future for your upcoming marriage?
Life isn't always fair but we can't let unfair happenings spoil our love and trust. Don't let your anxiety block your ability to receive your blessings!