I have had less than stellar success with the sex schedule concept. I'm not sure if repeatedly trying to get your spouse to agree to a sex schedule is really any more productive than simply boldly initiating/suggesting sex whenever you're in the mood. If you do this, your spouse might end up suggesting a schedule in order to avoid your "constant" advances and theoretically be more invested in the schedule since it will become apparent how it might benefit them also.
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver