L.H.
I would tell him about the baby. I think that he would want to know. With all endings there is a beginning... Maybe the news of the new baby will some how bring him comfort.
I understand how you feel about starting over at 36. I'm 35 right now will be 36 in April and am 26 weeks pregnant. I have two older children who are 9 and 5 yrs old. When this little one starts Kindergarten my oldest will be starting high school and my middle child will start middle school. Crazy! I was very nervous and scared when I first found out at 4 weeks. But now I'm looking forward to this new baby. Just give it some time to sink in.