Still can’t bring myself to clean my cum from my wife

I want to go down on my wife after I cum inside her, But I always lose interest as soon as I orgasm. Last night I felt like it was going to be the night and I was really turned on by the idea during our foreplay but I didn’t go through with it. I’ve told my wife that I am going to need her to ask me to taste us together for me to do it. She said she plans on surprising me some night soon with some encouragement to clean her up