While the interaction of their characters will be missed, having hooked the two of them up now, there are not a lot of places you can take them after this. Having slept together, they can never really have the same boss-employee relationship they had before, and Cuddy has lost her ability to stand up to House. Bureaucratically, he has sexual harassment to hold over her, and her having broken off the relationship, he's going to be the one indifferent to any remnants of their feelings or lashing out, while there is not a lot she can do to him without coming off as the bad guy, even more than she did in the early days when she was simply the kill-joy.