stung,
why are you scared to tell him you want to stay separated longer? what i remember hearing again and again (although i don't know anyone who actually follows this rule. most folks either get out or are desperately clinging to relationship) is that once an A seeks sobriety and recovery, they are not supposed to change (or is it be in a) relationship for a year and are supposed to totally focus on recovery for 1 year. After that year, both parties decide if they want to move forward with relationship.
you can always talk through it with him and agree to terms (i.e. no dating/dating, financial support. etc) like a contract. if you want to make it legal to protect yourself, i don't see a drawback to that. that gives you time to think and work on yourself without urgency and he understands seriousness and your boundaries.