Why Did She Do This

My wife has had plenty of lovers before me,
I can accept this apart from one.
He was much younger than her and for some reason this has become an obsession with me for the 40 plus years we have been married.
I have grilled her why someone so young and then what they did together.
Now this has now starting to turn me on.
I jerk off thinking about his young cock fucking my wife to be.
When we fuck and I go down on her, I cannot help thinking that his cock has been there!
Now I fantasise that she is being fucked by this “well boy really “ and I am on the bed watching them at it.
Then when he has finished having her..and has cum and moved from between her legs, I watch his young sperm trickle out of her!
Then I grab hold of his wet cock and take it in my mouth and suck him off.
Getting so turned on even writing this!I’m