To make things simpler I assume that getting and being in the following sentences have the same meaning. So I will use being as less colloquial.
I am being (getting) married. (passive)
This sentence is in the passive form. What would be the active form? I suppose:
Something is marrying me. (active)
Sounds to me like the object is in the middle of an action. The bride and groom stand before a priest who is reading the common lines. And the bride thinks: "I am being married."
But people say it long before the wedding:
I am being married in July. (Active ~ The church is marrying me in July.)
Congratulate me, I'm being married. (But he / she is not in the middle of a marriage.)
Wouldn't it be more accurate to say "I will be married in July." or "Congratulate me, I am going to be married." Because the marriage is a kind of a contract (a one shot deal.)
Best Answer
We have several different uses of marry and married in play. Some of the meanings deal with an act and others with a status.
There are two basic uses of marry, both relating to the act:
(most of the additional uses you will find in a dictionary, as to acquire something through marriage as in marry money, or to find a spouse, as in marry her daughter to the prince, derive from the first).
There are two non-overlapping senses of married, the first referring to the status, the second referring to the act:
The act of becoming a husband or wife (i.e. taking vows, participating in a wedding ceremony, signing legal papers, et al), represented by the first meaning of marry and the second meaning of married, is usually expressed as getting married. Thus, a native speaker would be more likely to say
You can say
but like all I am to V statements (I am to be named chief, I am to take the pills daily), it is formal and sounds somewhat stiff.
Usually, to say being married in referring to the act is usually to use the second sense of marry in the passive voice.
Otherwise, being married is often in the first sense of married, to be in a state of marriage with someone.