Do you think he will understand or see this is why I turn him down??
Tough to say because he is so pig-headed -- might have to beat it into him! Hopefully he'll reflect on the sitch and come to that conclusion, but if he doesn't then we can always hope another sitch (NOT like the lunch time one, though) will come about where you can express/explain this to him. Bottom line (IMO): before things can progress THIS MUCH needs to be understood.