You're not alone. Be assured you are not alone, nor are you sick , I don't care what your therapist says. I get too many calls from all over the globe for that to be true. The picture in your head isn't going away so have fun with it. I will tell you that spankers are different than most scene players.
Many spankers are embarrassed about their calling and try to deny it.
One of these types may best describe what runs through your head. Having a partner that does not understand is a very common predicament. I can give suggestions as to how to solve the problem but in the end it is up to your partner and how much they are willing to meet your needs. If they don't have the gene they cannot imagine how much this ritual consumes you. It is mind boggling to think that your calling for adult spanking is far less intrusive or medically contaminated than intercourse or many other rituals of love that partners experience.