Can you get the spark back?

My husband and I have been together for almost 16 years (married for 10 years). We have a four year old and a baby on the way. We do have arguments here and there. In June, we hit a really rough patch; I thought we would end up separating but we talked things through and decided we love each other to keep trying. Since then, I felt we haven’t been the same. What can I do to get the spark back or is it gone?