As I was reading it, I thought about the possibilities.
If she had a love interest with Voldemort, it would be a twist because of how close she is with the Golden Trio.
I'm trying to picture it with Lucius and it would work, but it wouldn't fit into the story as well, I would think.
But that's just my opinion =]
But, the question is, are you sure you want to put that into your story?