There is policy regarding a wait before re-applying for a visa, but this refers to a temporary visa once you departed Australia with unlawful status. It does not appear to apply in this case.
But your main issue may be the future (or current) Partner visa processing. The character issue may affect that and so you need to get a profession opinion on the character issue.
You may also have grounds to appeal the visitor visa (depending on what type of Partner visa you can lodge). It may be better to resolve character issues at the AAT with respect to the visitor visa, then use that decision to support the character issues on his Partner application.
You can email me the subclass 600 decision and we can then comment.