Well, I don't think my DH and I would have the reaction that you and your DH did to being separated for 4 days. That doesn't mean I wouldn't pout and be sad about it. I think we've spent a couple of one-nighters apart since our wedding, but that's it. It's not fun sleeping in bed without him.
Some "solo" time can be good for you, though. My DH spends at least one day/evening a week out with his buddies and it's nice to be alone.
Everyone has different relationships, though. Some couples only see each other on weekends, some have never spent a night apart. What would suck is if two people married who had very different notions about that sort of thing. I wouldn't like it if my DH could just go off for 4 days without sharing in some of the pouting I would be doing. If I'd married a different sort of man, he may feel I was being clingy.