Lately I'e found it useful to think about that "relationship obsession" that I think you're feeling (and that I know only too well myself), and compare it to the alcohol addiction. You know, what they must feel like if they've been off of it for a few days ... thinking to themselves, "I've been so good. What's the harm?" Just like we think, "I haven't called in like four days. I just want to see how s/he is doing." It's all a rationalization to continue doing something that isn't good for us. It's about allowing the addiction in for a stay and being glad to see it, old familiar friend that it is. It's a seduction in which we play ourselves.
Just some thoughts.