It might be more convenient to reignite interest in your partner by practicing self denial. Someday there will be a study demonstrating that no matter how many sexual partners you have, or how many implements you insert into yourself, you will eventually reach a point where you become numb to the maximum level of stimulation you can procure with your current resources. The next step is to go insane. A week under a vow of silence at a meditation retreat, or a month of moving bags of sand at a refugee camp, restores interest in sex without turning us onto a path of diminishing returns.