Since your friendship with this younger woman is something you can take or leave- why don't you leave it for at least a while. Let the friend know what is going on so she won't feel hurt and maybe tell your W that you've decided to not hang around with her until you W feels better about things. Does your W know that the friend is in a serious R? Tell her everything and tell her the truth and hope that in time she'll trust you again. What are the circumstances of your D? Who left who and why? Is this jealousy related to something from your previous R with your W before the the D? Hope this helps you. Take care.
