I recently learned that believing in something stronger than myself provided me strength to endure in times of strife and anxiety. It doesn't have to be some higher power or deity. It can be whatever it is that you need for that particular situation. Like, if you truly believe in your relationship, you can fall back on that in times of need. It's not good to always lean on it, but in times of need it can give you the support that you need to keep moving.
You'll notice that at no point in the preceding paragraph did I mention your wife or leaning on her for support. That should not be implied in what I wrote.
It may also help to take a look at and start
Understanding your role in the relationship if you have not already done so. We can sometimes unknowingly do things that can easily be changed that make matters worse. Why not change them?
This has the added benefit of focusing on you and what you can control. (As you've noted that's only yourself.) This will help reduce anxiety because you are focused on what is within your control rather than worrying about what is not.
What have you discovered about you that you can change?