Shinoda Haruka

The protagonist's sister in law.
Before marriage she was childhood friends with Touya and Shuugo.
Her husband often isn't around due to work so her sex life isn't that active and they don't have children.

She is a little lonely due to her husband's constant absence so she is often hanging around Touya, however she doesn't see him as the opposite sex so she is always defenseless around him.