Anxiety and your inner 'dictator'
The psychoanalyst Leslie Farber, had the interesting idea that anxiety was caused by willing that which cannot be willed (Farber distinguished between healthy fear and what he calls neurotic anxiety, where concern is excessive). This might sound mystifying, so an example will help: Say you overhear on the late-night radio that the roads in your area are hazardous, and you know that your partner, returning from a long journey, must traverse some of those roads. Naturally you will feel some fear and apprehension and you will hope that your partner will be safe. Where anxiety enters the picture - if it enters at all - is when you inwardly insist that your partner must be safe. Suddenly, you feel much more anxious and you wait desperately for their return. In other words, you try and use your will power to alter things that are not in your power to change: You will that which you cannot will.
How, then, does willing that which cannot be willed, transform ordinary fear into neurotic anxiety? According to this theory, your anxiety originates from an inner dictator of sorts, which insists that what you would prefer to happen must happen. Therefore the reason why a frightening outcome becomes even more alarming, is that you have taken something you are much invested in, and made the event or person even more critical to your well-being (saying that something must not happen transforms a very sad outcome into an absolute catastrophe); consequently, the thought of something going wrong is especially terrifying. In the above example, you might be standing at the door waiting for hours for your partner to return, because you are so anguished by your imaginings.
Related to the above, is that insisting that something frightening must not happen ironically makes you feel less in control. This is because if what you fear is not in your power to change, then trying to do so only makes you feel less powerful. The dangers of this is that a vicious circle can be established: Demanding can lead to feelings of impotence, which can then lead to trying to demand even more for things to go one's way and so on.
The discussion so far raises the question of how to address one's anxiety (understood in the above terms). Firstly, we are quite rightly taught about responsibility from an early age and it helps us to think carefully about the effects of our actions. But this tutelage can sometimes indirectly encourage us to take over-responsibility, especially where loved ones are concerned. Indeed, often when someone we care about is harmed in some way, we often say to ourselves, "if only I had done X, then it wouldn't have happened". Though we are being well meaning, we are nevertheless confusing wish with capability: Just because we wanted to prevent a certain outcome, doesn't necessarily imply that we had the ability or opportunity to do so. Understanding the limits of our control over others and over the world, will help prevent getting anxious over that which cannot be changed. This is not fatalism, but realism: It isn't saying you have no power or control, just that you recognise for the sake of your mental health that there are limits to what you can do.
Another helpful way of dealing with your anxiety is to realise that when you get too caught up trying to prevent through your willpower a dreaded event, you are becoming the director of your own horror movie. Obsession with getting one's way very often leads to visualising in one's mind, the unwanted event happening in all of its gory detail. Try and catch yourself doing it and remind yourself that a mental movie is just that; a figment of your imagination that has no great claim to credibility.
A final - and more definitive - way to tackle anxiety is to challenge the demands (irrational beliefs) that your inner dictator makes. Recognise that you can have legitimate preferences - e.g. you'd much prefer that your partner did not have a road accident - but dictating to the world ("my partner must not have an accident") only makes a difficult situation worse for the reasons given above. Repeatedly challenging the illogicality and the impracticality of these demands can win you - over time anyway - greater peace of mind.
Sometimes, it's easier to do this work with a counsellor, as often our irrational perspective is our world view and it's difficult to get distance from it, just like it is impossible to see your own eyes unaided. A good counsellor can help you uncover your irrational thinking and help you start to challenge it so that your anxiety lessens.