Mother and son have sex in 2 seconds after father goes out

Yui has something she hides from her husband. This means that he has had a relationship between a man and a woman with his son Toru. I knew it was a bad thing, but I ended up in the depths without listening to what my instincts said. At first, the secrets that my husband secretly did when he was on a business trip that he was never home escalated, and now, when his husband was gone, he started to seek out each other in two seconds...