I Was Seduced By My Stepdaughter

I am a 45-year-old man and I recently married a 49-year-old woman with a college-going daughter.

We met two years back at my cousin’s wedding and liked each other a lot. There weren’t any sparks flying but we were quite compatible. I hadn’t met her daughter before our marriage since she was studying in a college in the US and wasn’t very happy about our marriage. She came to live with us after six months and we became quite close.

I found it very difficult not to think about her and she being young and reckless, enjoyed the fact that she had my attention. One day when my wife had gone to her parents’ place, we had sex and it was very satisfying and she was better than anyone I had sex with before. She has now gone back to her college.
Should I tell my wife about it or should I quit secretly?