Phantom mother: I became a domestic stalker

I fell in love with Haruki, my father's new partner. She was originally my father's affair partner, and it's often called a predatory marriage. But that doesn't matter to me. I can't stand it being just a mother and son. I can't take my eyes off Haruki no matter where she is. Whether I'm changing clothes or masturbating in the bathroom, I feel like my insides are overflowing with thoughts of Haruki. Dad, I'll take it away this time...