"Get" + "married" can be either an adjectival passive or a verbal one:

In the former, "married" is an adjective; in the latter a past participle verb.

 

>[1]  *They are hoping to get married by the bishop.* (verbal passive)
> 
> 
> [2] *They are getting married at the weekend.* (adjectival)


In [1] the *by* phrase makes it clearly verbal, so "married" is a verb here. In [2] there is no explicit or implicit agent and, furthermore, "married" cannot combine with "become" (*“They became married”). "Married" is thus an adjective.

> [3] *They got engaged last month.*

"Get" + "engaged" is always an adjectival passive. "Engaged" is morphologically related to the past participle verb, but its meaning has changed so it is no longer comparable to a verbal passive. Further evidence of adjectivehood comes from the fact that it can combine with “become”, as in “They became engaged last month”. Only adjectives can  combine with “become”.