It is par for the course that not everybody puts in an exactly equal amount of time. Have you agreed upfront that you both were going to work exactly the same hours? Have you agreed on a specific number of hours? 70% of 60 to 70 hours is still pretty good, it's not like she's doing nothing.

I've been in your situation and it took me a while to realize that not everybody is like me. It could very well be that you spend a lot of time but achieve little and that they spend relatively little time but achieve lots.

Step back for a bit and try to objectively judge not the hours you put in but the amount of output you generate and whether or not this is more or less than what you agreed upon at the outset.

What you definitely need to do is to establish what exactly it is that you're expecting of each other.