One way to definitely improve your marriage, if you are a dad, is by helping your wife with the childcare duties. Just because you are a working parent, it doesn't mean you are actually doing more work. Taking care of kids is a lot of work and it is hard.
It used to be that dads were less involved in raising kids, but it is changing now, and it is great that more new dads are spending time with family, changing diapers, making sure their spouse gets equal sleep..etc. "Just because you are going to work it does not mean taking care of kids is somehow less work."