Bless your heart,
Have you tried talking to your other half about how you feel? They care for you and would hate to know you were suffering. Please consider talking with them about it, it might reduce the obsession if they are no longer on a pedestal, but your equal.
As a past sufferer, I am now married to a wonderful man and while I love spending quality time with him, I am not anxious when he's not around.
What is crucial is being able to spend time alone without worryng they will leave you or cheat. Tell your other half that you are spending time alone as personal investment. Then identify and chase your dreams, make them separate from your other half. Find yourself; what is your favourite pastime? Colour? What did you want to be when you grew up, travel? Sing? What makes you different and special compared to other people? Enjoy finding this out. Take up a course, learn something new, take a class for higher paid job one day, anything but build your strength AWAY from your other half.
The danger is you could push them away; if they sense you depend on them to live and breathe, they could feel resentment that THEY are not 'allowed' to live and breathe.
Friends are a great way to start. Hire a dvd, organise a night in and try it : ))