Wear the badge of the gamer with pride. When our daughter gets older both my wife and I will show her the joys of gaming as we both share an interest for it. Why should this form of entertainment be any less than showing your kid the joy of films, reading, art, or sports? All of these are things that people enjoy and spend their spare time doing, and gaming is the same. Been gaming since the late 80s and don't see any reason to stop any time soon. Of course, time becomes an issue when one chooses to take the responsibilities of the adult world, such as having a child, but the joy is still there when time allows.
Having a hobby as gaming has nothing to do with being a "man-child". As long as you are there for your family what you spend your free time on is your choice alone. I know I spend my time on FM (and here being a forum police) without any concerns about my adult status!