You mention the sex doesn't interest him. What does, what does he get excited about. If he likes sports, try being his cheerleader, if he likes cars, be his groupie. If he likes home improvement, perhaps you can ask him to build some bedroom accessories....

What I am getting at. If he doesn't see sex as a motivator, find what does motivate, and make it sexual.

Don't know if that helps or not.

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