I think you need to reassess what is truly good or bad for morale. The "ass-in-seat" mentality belongs in mega-corps and does more damage than good in a small team. As a founder, your goal should be to create a culture that encourages highly productive, self-managed individuals. You want to create a team that does more with less which requires trusting individuals to manage their time (ie. working hours).

Your question is regarding your co-founder's motivation but based on your tone and concerns, I would question if you have the motivation (or DNA) needed to run a startup. Not to say you are lazy; it seems your "values" are more in line with those of Big-5 Consulting or a Mega-Corp manager.