No, I don't think you are asking too much. It sounds like there's just some imbalance in your relationship, and this can be fixed.
Decide, first off, what is most important to you. Is it the sex, or your husband doing family time at the park, or his helping with the kids?
Then, write out a proposal. Guys seem to listen more to a game plan than they often do our emotions (which feel like a trap for some men. ugh.). Explain what you want him to do. "I'd like you to choose two games to watch during the weekend. After that, we'd like your company." This may make him think more deliberately how he's spending his time and prioritize.
Another idea would be to sit down on a Thursday night and make a plan for the weekend. When does he plan on doing some family activities? What about the shopping, or the trips to the park? When does he plan on training for the 1/2 marathon? Let him know that you would like to spend time with him too.
If it feels horrible, unworkable, go talk to a counselor. Sometimes, there are other issues in play that aren't as easy to focus on. Even the feeling of being lonely and deprived (and maybe taken for granted?) can work havoc and distress on us, and make some attempts at communication much more difficult and emotionally charged. There's nothing wrong with getting help in working things out *before* they get "bad". This is what healthy couples do, myself and my husband included.
I hope you find a resolution to your situation. I only have to "compete" with the Yankees, the Trailblazers, and Duke games, and it still feels very lonely some nights. I've decided to start movies without him, because I'm *not* waiting around while they go into overtime! Good luck!