Mizuki loves her husband, she really does... But for her, good dick is a need, not a want, and he just can't seem to deliver. Fortunately, she has a way of fulfilling her desires, and as long as she's home to care for her sweetheart at the end of the day, what's the harm in a fling or two on the side?
Seriously, though Atelier Sakura stories hasn't been as great as the ones it the past, you have more freedom in your doujins and you have such a great talent.