The affair with my step mom real homemade step fantasy with dirty relationship

It was a long time since my stepdad was married to my stepmother she was my stepdad's secretary. After marrying my stepdad I feel she was not happy because my stepdad didn't satisfy her completely. She was very honry i feel it she want somting with with me but was afraid of my stepdad. I take full advantage with this situation and make dirty relationship with her. This is our pure and homemade sex fantasy and stepdad doesn`t know