I for one don't think there is a set age for this...
So sorry to hear that your husband is among the many who has been out of work...that addition to the house would have been nice at this time but don't give up hope. Things do change and so will this situation.
Me and my brother ((((he has passed on))))were two years apart....him being older. We shared a bed room as children and it continued on until he went off to college and I finally got my own apartment. Although me and my brother got along great...especially as teenagers, it wasn't always easy sharing a room but as we grew up, Mom made changes in decordating this room to fit both our needs. I must say it did work out well, we both survived it and grew into being decent adults....
Like back then people now have to learn how to make due and for most, it hasn't been an easy adjustment...
Hang in there, wishing you a lot of luck with the new baby coming. I'm an April baby too...fasten your set belt sweetie as April babies are full of life, creative and born leaders...lol.