Because at this point...

"Not to night dear I have a head ache".
Besides it is not Wenesday.

... I would be hitting my computer/grocery store/local bar for someone that would be willing to do it more than once a week and in new positions.

BDSM_Tourguide doesn't play the "withhold the sex" game. BDSM_Tourguide goes looking elsewhere for it if that becomes an issue.