Completely different Michael at the wedding than the man at the end of the movie. In the beginning, Michael thought he was above it all. He thought he was going to be a professor, married to a WASP like Kay, completely legitimate. He had no idea the twists and turns his life would take. He was trying to ease Kay into understanding what his family was. But that was his family, not him!

As for lying at the end, of course he did. And of course she knew it.