What should I do when a dead person keeps crossing my mind when I am intimate?

Whenever I am intimate with myself or another my passed away grandpa crosses my mind, i keep trying to force it to go away but it keeps happening and i immediately feel super weird. I’ve heard that other people sometimes also experience this but it’s just so annoying. I feel watched when it happens, and utterly disgusting. I just want it to go away and be intimate without any problems. What should i do?