That has to be an awkward moment.
"Kaiden, dear, did you hit your head during that explosion in ME 1? Cause you seem to have a whole set of memories I do not have." 
They did that on purpose...
for exemple the z'etero..get the liara Talk even though they may not have had any romance with her..although Im told that is a glitch . And peoples whined about it as well...'ewww why that alien freak think we had a thing' .
They made it so....ya dont get locked in a romance if ya wanna pursue someone else . Still..if ya are faithful and bring a save from Mass effect 1..I wish the game could recognize that once ya are locked say with Liara or Samara...and add a tiny bit to that effect . Instead...her romance talk isnt much different then a friend one...