It may not be so much punishing but maybe that you have been able to hide yourself away from your marriage through the anorexia. Putting your focus & energy that you would normally want to put into a good marriage, get's put into the exercise. I graduated from college & got into a wonderful firmware engineering career. Since my marriage was bad from the beginning, I put all my energy & all myself into my career. When I lost my career 15 years later when the aerospace industry went downhill, & I then felt trapped in the marriage, that was when depression & the anorexia hit & provided good reasons to keep at a distance from my husband & he even might have been a little concerned about how I was. Also gave me something to focus on since I no longer had a demanding career to focus on any longer & that focus filled a need that I had so I was happy with it also.

Can understand what you say:
Your exercise & eating routine is probably filling a void in your life that would otherwise be filled with a happy marriage. However, I do know of people who have a happy marriage, but got into the ED behavior & it became a habit. Think it's even harder to control when not only is it a behavioral habit, but also filling the void of unhappiness......just a thought.