usually the producers know people tune in to more drama than an hour of happy time.. so they put a lot of drama scenes and of course have to squeeze the happy moments in there cuz it is about them learning about life and children and growing up.
shareLike meggalove said, apparently Sean and Kelsey didn't have enough drama going on for the producers to want to air more clips of them. Sean and Kelsey have been practically nonexistent since the toddlers episode.
Well, sometimes nothin' can be a real cool hand.share
Also, I think it might have to be that Kelsey and Sean are...let's just say "less photogenic" than the other couples. I think that the producers may have chosen to focus on the more visually appealing couples. Plus, there wasn't a lot of drama going on with them, like others have said, which certainly didn't help them.
Living is easy with eyes closed