"A man can be happy with any woman as long as he does not love her."
In Demon Knights 16 it is confirmed that the Amazons are immortal. The Amazon on the team didn't change a bit in 30 years.
About the immortality thing, I was re-reading all WW issues and this speech by Hermes to Diana got my attention: "You are young. I think the concept of immortality is something you don't grasp yet. Diana... being immortal is a blessing, and a trap. A trap mortals don't share." That heavily implies she is in fact immortal.
Velvet: The Unusual Superheroine!
Yes sir. It was already mentioned in this topic... I just thought Hermes' speech offers some additional clarity because it was directed to Diana herself.