The marriage thing

This weekend my husband and I had a fight. I'm sure you're thinking 'big deal, all husbands and wives fight', but for me it kind of is a big deal. We've been married for twelve years now and I can probably count on one hand the number of times we've had a fight. Oh, and just to clarify, by fight I mean argument. Nothing physical. It was kind of a dumb argument in retrospect, but at the time it didn't feel like it. 

As most of you know the past several months I've been watching what I eat and exercising regularly so I can get in shape. Well my husband has been doing the same thing to an extent. For him it's mostly been cutting back on what he eats, he rarely exercises. Apparently he's lost a few pounds and guess what? I didn't notice. Basically he fussed at me because I don't pay him enough attention and I got mad because he was being mean. I know, we sound like a couple of two year olds right?  
Afterwards I was thinking about it and came to the conclusion that umm, he's probably right. When it comes to my kids I notice everything. If they get a bruise or scratch I notice. If they come home from school with a stain on their shirt or with their hair messed up I notice. If they don't eat all of their breakfast I notice. However with my husband unless it's a huge thing I don't notice. I kind of want to blame it on being a mom and just not having the time or attention span after dealing with my kids, but really for me that's a cop out. I'm just being lazy.
So I'm going to try to make more of an effort to be attentive. Because when you think about it if I don't pay attention to him then he could always turn around and do the same thing to me and I definitely don't want that.  Do any of you have this same issue? If so how have you dealt with it?