In ancient Sparta, the age at which men married could vary, but it was generally common for Spartan men to marry in their late 20s or early 30s. This was relatively older compared to some other ancient Greek city-states where men might marry in their late teens or early 20s.
Spartan society placed a strong emphasis on military training and service. Young Spartan men underwent rigorous training in the agoge, an educational system designed to produce skilled warriors and disciplined citizens. Because of this military focus, Spartan men typically delayed marriage until they had completed their military training and service.
As for the age of their brides, Spartan girls generally married in their late teens or early twenties. The marriage age for women was also later than in other ancient Greek cultures, where young girls could be married off at a much younger age.
In regards to the practice of marrying multiple wives, it was not common among ordinary Spartans. Polygamy was not widely practiced in ancient Greece, including Sparta. Only the wealthiest and most influential Spartans might have had multiple wives, but it was still relatively rare.
In summary, Spartan men usually married in their late 20s or early 30s, and Spartan women typically married in their late teens or early 20s. While some wealthy Spartans might have had multiple wives, the practice of polygamy was not widespread in Spartan society.