A neighbor woman told me her secret for motivating her husband was to tell him, “It would really turn me on if (insert task) was done.” Of course she had to follow through if he finished the job but I suspect she enjoyed it, too.
There was a book out a while back called Sex Begins in the Kitchen.
I knew a couple that had a rough marriage. One day he decided to help do the dishes and her comment was that it almost made her want to have sex with him.
There is NOTHING like validating the other person by making them like they are worth something to you.