Appropriate amount of "wind down" time?

So I work from 4pm-10:30pm and then am normally in bed by 11:30pm because my son gets up at 8am. My husband works 3-11:00pm and stays up until 4am to "wind down" and won't get up until noon or later each day. Its super annoying and he never has time to help with anything in the house or our son. I'm 23 weeks pregnant so I could really use the extra help. How much time do you take after work to wind down before going to bed?