The importance of communication in a marriage, or indeed in any relationship, cannot be overstressed. You have to sit down with him and talk to him about it. It might be that he hasn't even noticed that he spends most of his time away. Make him understand that you need him at home too, but don't make him feel like you are being controlling.
You should try discussing this with him and let him know how you feel. If he cares then he will realize what he's doing and try to spend more time with you. He may just not realize that he's upsetting you. Maybe try spending some more time with him and going out more often? :)
This doesn't sound like its going to end well for you. I've found in my experience and those of my friends, whenever we are committed to someone we tend to "let ourselves go"a bit. Only time we start bringing sexy back is when we are single.