I didn't like the way that was written either. Though in my story I did make Katherine more attracted to Henry. I wanted Henry to be a likeable character in the story so, instead of him being a lech, he genuinely cares for Katherine, but at the same time, the opportunities to show his politics and money schemes were too good to miss so that's also one of his motives for wanting to marry her. In every other respect, his character does follow the idea of what Henry would have been like. Henry VII was one of the greatest political schemers of his day, and I say that in the nicest sense possible.