This should not be the case. If a couple is marked as divorced, you should not see "## birthday of X, X is married to Y".
If you find that a divorced couple is listed as being married, check a few things first:
1. Make sure there is a divorce fact for the couple in question (separation, anullment, etc. are not the same thing).
2. Make sure there is only one entry in your tree for both of the individuals involved.
3. In the Site Members list on your family site, view the profile of each member and check their association to the family tree. Are they associated to the correct individual in the tree?
If you find that the above is correct and the couple is still shown as being married, please give me the names of the individuals and I will check to make sure we don't have a bug that is causing the erroneous relationship.