Its easiest to tell others about your dx when stable in my experience so they don't feel you're making excuses for your behaviors. Also, they see you are stable and rational, so they know you are doing your best to treat it. They will have a lightbulb moment looking back at the times you may have gone a little nuts.

When I told my boyfriend we were just getting started in our relationship. I said "there's something I need to tell you" (pause) "I'm bipolar." His response was "That's it?? I thought you were going to say you were a serial killer or something bad!"

Its been 3 years. He loves me for me and understands that bipolar is a part of me. (Yes I know I'm not my disease, but we come as a package deal). He says it's ok as long as you are actively treating it Episodes and hospitalizations are bound to happen (and have) but he doesn't mind as long as i'm trying to help myself.

Keep us posted on how that conversation goes.

It is definitely scary, but its will come out eventually.