Here are a couple of interesting articles that I ran into.
One deals with whether or not humans have peaked - Peaked Performance
The second article deals with endurance sports and relationships - A Workout Ate My Marriage
The second could bring up the most discussion. It deals with a man in his mid-40's who is now training 20 plus hrs a week and seems to ignore his family. The second part of the article does mention a husband and wife, one who is a couch potato and the other who works out, but the relationship is going well. The one thing I hate about this article is that the two families are completely different. The first family is family with 3 kids. The other is just a husband and wife. This article seems to take both extremes and makes them seem standard. I'm sure there are families that are able to handle the endurance sports well. Everything is always about setting priorities and sticking to them. Family should comes first.