In the dictionary
get married: to become joined in marriage
They're planning to get married in October.
married (adj): having a husband or wife
So, this is what I think
we often say "I'm married" which means "I have a husband or wife", we don't say "I get married".
We say "I was married" which means "I had a husband or wife in the past but I may or may not have a husband now"
We say "I got married" which is nearly the same as "I had a wedding"
get married (=to have a wedding)
Did you know that they are going to get married?