I would say not that much, to be honest. We both have two jobs, I go to school, we're both really involved with our respective families a lot.
During the week, we're together most mornings for a few hours, but we're both getting ready for work/our days, so we're talking a lot but not hugely deep conversations. During the week, most evenings we don't both get home until like 815, an "early" us evening is 615, and then we usually hit the gym "together" for about an hour. At the gym, we don't really talk or interact but to encourage each other occasionally.
After the gym during the week we either hang out and have us time for a few hours, or see friends. Togetherness time or friendship time tends to last about 4-5 hours. I'd say on average, we spend 1-2 days with friends during the week, and 3-4 days just the two of us. Our hanging out together time involves me reading and him playing video games sometimes, or him doing dishes and my tidying up the place. A lot of conversation in either case, but the focus isn't really on "us". I fall asleep before he does lately (since he got his surgery for sleep apnea he's a whole new man!!!!!

) unless we're going to have sex. We have sex probably about 3-4 times a week hahaha so sex takes up a decent amount of our together time.
During the weekend, I usually see him for a very little while Sat. morning during which he gets ready for work. If I'm working I'm outta the house by the time he gets up. He spends Sat. night into Sunday on the ambulance a state away, and I usually get s***faced with my friends.

I usually don't see him 'til I get out of work on Sunday (around 5), at which point I go visit he and his parents in NH or he comes home and we see my parents typically. Or sometimes I go out on Sunday nights and we don't see each other until Mon. morning.
We're both very independant, we're both only children, and this really, really works for us. We get to be together, and if one of us is feeling disconnected we try to make more time. I think that's what's key, we're both happy not having a huge amount of focused "us" time. I get the bittersweetness of missing him on weekends, and he's really cool about trusting me so I get to go out and spend time with my friends and family and heck, even by myself on weekends.
Question, have you tried engaging her? Have you tried maybe suggesting something fun, like a board game or something? Have you even just told her "I miss talking with you"? I'm an avid reader myself, and sometimes I can be a little neglectful and get too caught up in what I'm reading and not M. He'll just call me out on it, ask me to stop, and have something for us to do together, even if it's just giggle at episodes of "Queer Eye" together.