I imagine our child will be involved heavily. As for a spouse, well they could add them, BUT, if your a mega-badarse wouldn't you think your spouse, who you could potentially play as, would be just as driven as you? You could quite easily make an argument against that statement but still...
I imagine our child may have the same role as, say, Doctor Li. Not essential entirely to the story but will involve his own thing. He will of course have a much larger role than Li, but I mean it in the same style as him being integral, but not truly the main "goal" of the overall story. Sort of how the goal was find dad, well you find him, and then he soon after is no longer a part of the overall goal of defeating the Enclave and restoring Project Purity. Not in the same way, but he will become and accessory to the rest of the game whether he is still a child or grown man.