Like Ed and Su.Ki have said, the second sentence is incorrect. If you really wanted to use the word "during" in this case, you would need to rewrite it as "we have been married during the past two years" The problem with this sentence tho, is that it has a different meaning and sounds strange. Using "during" makes it vague as to how long you have been married as the sentence could mean that you were married before the two years, for the full two years, or just a section of time during the two years. Hope this helped :)

Your question should be 'Is there a difference between the sentences?' And the answer is 'yes' - only the first one is correct. If a couple got married in November 2012, they would say 'We have been married for two years'. You can't use 'during' followed by a length of time. The second sentence is wrong.

The first is right; the second doesn't make sense. During is used to express what was done in a time interval, not how long it has been since it started. So, we have been married for two years. During those two years, we have done many exciting things.