Eva, I am so glad you asked how do I keep the spark in my marriage! The word "Spark" is so apropos is because I usually think of a Fireman when Lou and I are getting frisky! I sometimes fantasize that Lou is driving a fire truck up to the trailer and saving me right there in bed!
Also, I know it sounds corny but I love walking with Lou at the end of the day, it is the only kind of romantic date we could always afford and is still turns me on.
Keep the spark??? I've not been married, but I'd say hook him up to some jumper cables & that should light him up "purty good"