Answer
Bad credit can be overcome. your first step should be to talk to a mortgage broker to see what can be done. while you may have bad credit, your partner might not and the promissory note can be put in his name with both of your names on the mortgage and title. but since we are talking about a "partner" and not a legal relationship like marriage this might be a risk to the partner who has their name on the promissory note if you were to break up. so, your partner could solely title the house in their name until a time when you repaired your credit and could refinance in both of your names or until the time they legalize civil unions.