Le is an eventive marker that reports the actualization/realization of an event in time. When it follows right after a verb, it indicates the verb is actualized; When it follows an VP (Verb Phrase), it marks the whole VP as realized in time. The so-called ‘sentence-final le’ emphasizes the realization of the VP as it is time-relevant and thus more likely to be relevant to the current discourse.
我結了婚 (wǒ jié le hūn) only asserts the actualization of the verb 結. It semantically equals “I was married” in English.
我結婚了 (wǒ jié hūn le) asserts that the verb phrase 結婚 is realized. It semantically means “I am married / I have been married.”
我結了婚了 (wǒ jié le hūn le) is the combination of the phrases mentioned above, asserting the realization of the action 結 as well as the change of state 我結了婚.
Reference: Chinese: a linguistic introduction by Chao Fen Sun