Joint gifts do not mean that you are portraying a happy family. It means that you are both contributing to a gift that your son wants.
What were you planning on giving your son for a gift? Does your h's request make sense or is it unreasonable?
If it's what YOU want to do then do it. If it isn't what YOU want then nicely let your h know that you have already purchased gifts for s, but thanks for asking.
Keep it simple!
Me 50 H 42 S 22 S 9 D 7 M 12 T 17 H moved out 8/2006 H moved home 1/2007 for 3 weeks H moved home 5/2011 for good
"Learn from yesterday ~ Live for today ~ And hope for tomorrow"