Need Help Figuring Out Timing Sex with IUI

How do you time sex with IUI so you don't deplete sperm count for insimination? I don't want to miss chances to have sex but want to make sure sperm sample is good. doctor said to have sex every other day. 
Here's where I'm at: 
CD 11: Neg OPK, no sex
CD 12: Neg OPK, sex
Today is CD 13: Neg OPK, should we have sex today? 
Tomorrow is CD14: likely positive OPK, should we skip sex on CD 14?
CD15: likely IUI, DH provides sample and we "top me off" in the evening. 
Should we have sex today and tomorrow? today but not tomorrow? tomorrow but not today? 
Thanks for your help!