I think setting your work schedules so your child can spend most of her time with her parents rather than at a daycare is really admirable. Obviously it's also very tough on you two as a couple.
That being said, it's also important that there is
some time in the course of your week or weekend that you two can spend time together. Arrange your duties so if you both have weekends off, the entire time isn't spent catching up on household chores. That's no fun.
When was the last time you two went on a date? It doesn't really matter what you do as long as you both treat your time together as something special. That means when you make a date with each other, keep it! It's important. Just because you're married, it doesn't mean you should stop wooing each other.
This is going to sound silly, but if you're both out of the habit, take just a couple minutes every single day to think loving thoughts about each other. When things are tense it's far too easy to fall into thinking about only the things we don't like about our partner or relationship. Negative thoughts snowball and left unchecked, will eclipse positive ones. A sure sign that your relationship is really in need of some TLC is if it's difficult for either of you to easily think of 3 lovable traits about the other. It doesn't mean the relationship is over, just that some negative thinking needs to change.
It sounds like you really love your wife and family and know they're worth fighting for. The best of luck to you.