He was convicted and released years before he met her. I'm inclined to agree that it could be a headache for Opposition Leader or PM Plibersek in a way that it isn't for Deputy Plibersek, but let's at least get the story straight.Because it's going to be a distraction that is going to drag her down and be a huge media circus no matter what.
This isn't some guy smoking pot in college or something, he was convicted for dealing heroin. The exact same problem would exist if she was a man and her husband was a woman.
The situation is more complex but it's irrelevant because it's hard to explain why the husband of a potential prime minister was involved in the distribution and dealing of a drug that just about everyone agrees is a huge net negative to society. It's not going to play well with the majority of people and people are going to judge her for not ditching him long ago.