I guess you can wait until it becomes apparent to him, but I do not know if that would be a good idea. I think it is unreasonable to think that you will be able to with any confidence control when this happens. After all, we are mentally ill. So I think your decision needs to be made with this also in mind.

I think there is wisdom in a mention of the golden rule by a previous poster, that which may not be self-evident to some. IMO I think before the relationship gets too serious, the topic will need to be discussed in some fashion. This would be a thoughtful, considerate, caring thing for you to do for him that could avoid allot of problems in the future for the both of you.

FWIW